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1 /*
2  * Copyright 2014 Google Inc. All rights reserved.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *     http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #include "idl_gen_ts.h"
18 
19 #include <algorithm>
20 #include <cassert>
21 #include <cmath>
22 #include <iostream>
23 #include <unordered_map>
24 #include <unordered_set>
25 
26 #include "flatbuffers/code_generators.h"
27 #include "flatbuffers/flatbuffers.h"
28 #include "flatbuffers/flatc.h"
29 #include "flatbuffers/idl.h"
30 #include "flatbuffers/util.h"
31 #include "idl_namer.h"
32 
33 namespace flatbuffers {
34 namespace {
35 struct ImportDefinition {
36   std::string name;
37   std::string import_statement;
38   std::string export_statement;
39   std::string bare_file_path;
40   std::string rel_file_path;
41   std::string object_name;
42   const Definition *dependent = nullptr;
43   const Definition *dependency = nullptr;
44 };
45 
46 struct NsDefinition {
47   std::string path;
48   std::string filepath;
49   std::string symbolic_name;
50   const Namespace *ns;
51   std::map<std::string, const Definition *> definitions;
52 };
53 
TypeScriptDefaultConfig()54 Namer::Config TypeScriptDefaultConfig() {
55   return { /*types=*/Case::kKeep,
56            /*constants=*/Case::kUnknown,
57            /*methods=*/Case::kLowerCamel,
58            /*functions=*/Case::kLowerCamel,
59            /*fields=*/Case::kLowerCamel,
60            /*variables=*/Case::kLowerCamel,
61            /*variants=*/Case::kKeep,
62            /*enum_variant_seperator=*/"::",
63            /*escape_keywords=*/Namer::Config::Escape::AfterConvertingCase,
64            /*namespaces=*/Case::kKeep,
65            /*namespace_seperator=*/"_",
66            /*object_prefix=*/"",
67            /*object_suffix=*/"T",
68            /*keyword_prefix=*/"",
69            /*keyword_suffix=*/"_",
70            /*filenames=*/Case::kDasher,
71            /*directories=*/Case::kDasher,
72            /*output_path=*/"",
73            /*filename_suffix=*/"_generated",
74            /*filename_extension=*/".ts" };
75 }
76 
TypescriptKeywords()77 std::set<std::string> TypescriptKeywords() {
78   // List of keywords retrieved from here:
79   // https://github.com/microsoft/TypeScript/issues/2536
80   return {
81     "arguments", "break",    "case",      "catch",      "class",      "const",
82     "continue",  "debugger", "default",   "delete",     "do",         "else",
83     "enum",      "export",   "extends",   "false",      "finally",    "for",
84     "function",  "if",       "import",    "in",         "instanceof", "new",
85     "null",      "Object",   "return",    "super",      "switch",     "this",
86     "throw",     "true",     "try",       "typeof",     "var",        "void",
87     "while",     "with",     "as",        "implements", "interface",  "let",
88     "package",   "private",  "protected", "public",     "static",     "yield",
89   };
90 }
91 
92 enum AnnotationType { kParam = 0, kType = 1, kReturns = 2 };
93 
94 template<typename T> struct SupportsObjectAPI : std::false_type {};
95 
96 template<> struct SupportsObjectAPI<StructDef> : std::true_type {};
97 
98 }  // namespace
99 
100 namespace ts {
101 // Iterate through all definitions we haven't generate code for (enums, structs,
102 // and tables) and output them to a single file.
103 class TsGenerator : public BaseGenerator {
104  public:
105   typedef std::map<std::string, ImportDefinition> import_set;
106 
TsGenerator(const Parser & parser,const std::string & path,const std::string & file_name)107   TsGenerator(const Parser &parser, const std::string &path,
108               const std::string &file_name)
109       : BaseGenerator(parser, path, file_name, "", "_", "ts"),
110         namer_(WithFlagOptions(TypeScriptDefaultConfig(), parser.opts, path),
111                TypescriptKeywords()) {}
112 
generate()113   bool generate() {
114     generateEnums();
115     generateStructs();
116     if (!parser_.opts.ts_omit_entrypoint) { generateEntry(); }
117     if (!generateBundle()) return false;
118     return true;
119   }
120 
GetTypeName(const EnumDef & def,const bool=false,const bool force_ns_wrap=false)121   std::string GetTypeName(const EnumDef &def, const bool = false,
122                           const bool force_ns_wrap = false) {
123     if (force_ns_wrap) { return namer_.NamespacedType(def); }
124     return namer_.Type(def);
125   }
126 
GetTypeName(const StructDef & def,const bool object_api=false,const bool force_ns_wrap=false)127   std::string GetTypeName(const StructDef &def, const bool object_api = false,
128                           const bool force_ns_wrap = false) {
129     if (object_api && parser_.opts.generate_object_based_api) {
130       if (force_ns_wrap) {
131         return namer_.NamespacedObjectType(def);
132       } else {
133         return namer_.ObjectType(def);
134       }
135     } else {
136       if (force_ns_wrap) {
137         return namer_.NamespacedType(def);
138       } else {
139         return namer_.Type(def);
140       }
141     }
142   }
143 
144   // Save out the generated code for a single class while adding
145   // declaration boilerplate.
SaveType(const Definition & definition,const std::string & class_code,import_set & imports,import_set & bare_imports)146   bool SaveType(const Definition &definition, const std::string &class_code,
147                 import_set &imports, import_set &bare_imports) {
148     if (!class_code.length()) return true;
149 
150     std::string code;
151 
152     code += "// " + std::string(FlatBuffersGeneratedWarning()) + "\n\n" +
153         "/* eslint-disable @typescript-eslint/no-unused-vars, @typescript-eslint/no-explicit-any, @typescript-eslint/no-non-null-assertion */\n\n";
154 
155     for (auto it = bare_imports.begin(); it != bare_imports.end(); it++) {
156       code += it->second.import_statement + "\n";
157     }
158     if (!bare_imports.empty()) code += "\n";
159 
160     for (auto it = imports.begin(); it != imports.end(); it++) {
161       if (it->second.dependency != &definition) {
162         code += it->second.import_statement + "\n";
163       }
164     }
165     if (!imports.empty()) code += "\n\n";
166 
167     code += class_code;
168 
169     auto dirs = namer_.Directories(*definition.defined_namespace);
170     EnsureDirExists(dirs);
171     auto basename = dirs + namer_.File(definition, SkipFile::Suffix);
172 
173     return SaveFile(basename.c_str(), code, false);
174   }
175 
TrackNsDef(const Definition & definition,std::string type_name)176   void TrackNsDef(const Definition &definition, std::string type_name) {
177     std::string path;
178     std::string filepath;
179     std::string symbolic_name;
180     if (definition.defined_namespace->components.size() > 0) {
181       path = namer_.Directories(*definition.defined_namespace,
182                                 SkipDir::TrailingPathSeperator);
183       filepath = path + ".ts";
184       path = namer_.Directories(*definition.defined_namespace,
185                                 SkipDir::OutputPathAndTrailingPathSeparator);
186       symbolic_name = definition.defined_namespace->components.back();
187     } else {
188       auto def_mod_name = namer_.File(definition, SkipFile::SuffixAndExtension);
189       symbolic_name = file_name_;
190       filepath = path_ + symbolic_name + ".ts";
191     }
192     if (ns_defs_.count(path) == 0) {
193       NsDefinition nsDef;
194       nsDef.path = path;
195       nsDef.filepath = filepath;
196       nsDef.ns = definition.defined_namespace;
197       nsDef.definitions.insert(std::make_pair(type_name, &definition));
198       nsDef.symbolic_name = symbolic_name;
199       ns_defs_[path] = nsDef;
200     } else {
201       ns_defs_[path].definitions.insert(std::make_pair(type_name, &definition));
202     }
203   }
204 
205  private:
206   IdlNamer namer_;
207 
208   std::map<std::string, NsDefinition> ns_defs_;
209 
210   // Generate code for all enums.
generateEnums()211   void generateEnums() {
212     for (auto it = parser_.enums_.vec.begin(); it != parser_.enums_.vec.end();
213          ++it) {
214       import_set bare_imports;
215       import_set imports;
216       std::string enumcode;
217       auto &enum_def = **it;
218       GenEnum(enum_def, &enumcode, imports, false);
219       GenEnum(enum_def, &enumcode, imports, true);
220       std::string type_name = GetTypeName(enum_def);
221       TrackNsDef(enum_def, type_name);
222       SaveType(enum_def, enumcode, imports, bare_imports);
223     }
224   }
225 
226   // Generate code for all structs.
generateStructs()227   void generateStructs() {
228     for (auto it = parser_.structs_.vec.begin();
229          it != parser_.structs_.vec.end(); ++it) {
230       import_set bare_imports;
231       import_set imports;
232       AddImport(bare_imports, "* as flatbuffers", "flatbuffers");
233       auto &struct_def = **it;
234       std::string declcode;
235       GenStruct(parser_, struct_def, &declcode, imports);
236       std::string type_name = GetTypeName(struct_def);
237       TrackNsDef(struct_def, type_name);
238       SaveType(struct_def, declcode, imports, bare_imports);
239     }
240   }
241 
242   // Generate code for a single entry point module.
generateEntry()243   void generateEntry() {
244     std::string code;
245 
246     // add root namespace def if not already existing from defs tracking
247     std::string root;
248     if (ns_defs_.count(root) == 0) {
249       NsDefinition nsDef;
250       nsDef.path = root;
251       nsDef.symbolic_name = file_name_;
252       nsDef.filepath = path_ + file_name_ + ".ts";
253       nsDef.ns = new Namespace();
254       ns_defs_[nsDef.path] = nsDef;
255     }
256 
257     for (const auto &it : ns_defs_) {
258       code = "// " + std::string(FlatBuffersGeneratedWarning()) + "\n\n" +
259         "/* eslint-disable @typescript-eslint/no-unused-vars, @typescript-eslint/no-explicit-any, @typescript-eslint/no-non-null-assertion */\n\n";
260 
261       // export all definitions in ns entry point module
262       int export_counter = 0;
263       for (const auto &def : it.second.definitions) {
264         std::vector<std::string> rel_components;
265         // build path for root level vs child level
266         if (it.second.ns->components.size() > 1)
267           std::copy(it.second.ns->components.begin() + 1,
268                     it.second.ns->components.end(),
269                     std::back_inserter(rel_components));
270         else
271           std::copy(it.second.ns->components.begin(),
272                     it.second.ns->components.end(),
273                     std::back_inserter(rel_components));
274         auto base_file_name =
275             namer_.File(*(def.second), SkipFile::SuffixAndExtension);
276         auto base_name =
277             namer_.Directories(it.second.ns->components, SkipDir::OutputPath) +
278             base_file_name;
279         auto ts_file_path = base_name + ".ts";
280         auto base_name_rel = std::string("./");
281         base_name_rel +=
282             namer_.Directories(rel_components, SkipDir::OutputPath);
283         base_name_rel += base_file_name;
284         auto ts_file_path_rel = base_name_rel + ".ts";
285         auto type_name = def.first;
286         auto fully_qualified_type_name =
287             it.second.ns->GetFullyQualifiedName(type_name);
288         auto is_struct = parser_.structs_.Lookup(fully_qualified_type_name);
289         code += "export { " + type_name;
290         if (parser_.opts.generate_object_based_api && is_struct) {
291           code += ", " + type_name + parser_.opts.object_suffix;
292         }
293         code += " } from '";
294         std::string import_extension =
295             parser_.opts.ts_no_import_ext ? "" : ".js";
296         code += base_name_rel + import_extension + "';\n";
297         export_counter++;
298       }
299 
300       // re-export child namespace(s) in parent
301       const auto child_ns_level = it.second.ns->components.size() + 1;
302       for (const auto &it2 : ns_defs_) {
303         if (it2.second.ns->components.size() != child_ns_level) continue;
304         auto ts_file_path = it2.second.path + ".ts";
305         code += "export * as " + it2.second.symbolic_name + " from './";
306         std::string rel_path = it2.second.path;
307         code += rel_path + ".js';\n";
308         export_counter++;
309       }
310 
311       if (export_counter > 0) SaveFile(it.second.filepath.c_str(), code, false);
312     }
313   }
314 
generateBundle()315   bool generateBundle() {
316     if (parser_.opts.ts_flat_files) {
317       std::string inputpath;
318       std::string symbolic_name = file_name_;
319       inputpath = path_ + file_name_ + ".ts";
320       std::string bundlepath =
321           GeneratedFileName(path_, file_name_, parser_.opts);
322       bundlepath = bundlepath.substr(0, bundlepath.size() - 3) + ".js";
323       std::string cmd = "esbuild";
324       cmd += " ";
325       cmd += inputpath;
326       // cmd += " --minify";
327       cmd += " --format=cjs --bundle --outfile=";
328       cmd += bundlepath;
329       cmd += " --external:flatbuffers";
330       std::cout << "Entry point " << inputpath << " generated." << std::endl;
331       std::cout << "A single file bundle can be created using fx. esbuild with:"
332                 << std::endl;
333       std::cout << "> " << cmd << std::endl;
334     }
335     return true;
336   }
337 
338   // Generate a documentation comment, if available.
GenDocComment(const std::vector<std::string> & dc,std::string * code_ptr,const char * indent=nullptr)339   static void GenDocComment(const std::vector<std::string> &dc,
340                             std::string *code_ptr,
341                             const char *indent = nullptr) {
342     if (dc.empty()) {
343       // Don't output empty comment blocks with 0 lines of comment content.
344       return;
345     }
346 
347     std::string &code = *code_ptr;
348     if (indent) code += indent;
349     code += "/**\n";
350     for (auto it = dc.begin(); it != dc.end(); ++it) {
351       if (indent) code += indent;
352       code += " *" + *it + "\n";
353     }
354     if (indent) code += indent;
355     code += " */\n";
356   }
357 
GenDocComment(std::string * code_ptr)358   static void GenDocComment(std::string *code_ptr) {
359     GenDocComment(std::vector<std::string>(), code_ptr);
360   }
361 
362   // Generate an enum declaration and an enum string lookup table.
GenEnum(EnumDef & enum_def,std::string * code_ptr,import_set & imports,bool reverse)363   void GenEnum(EnumDef &enum_def, std::string *code_ptr, import_set &imports,
364                bool reverse) {
365     if (enum_def.generated) return;
366     if (reverse) return;  // FIXME.
367     std::string &code = *code_ptr;
368     GenDocComment(enum_def.doc_comment, code_ptr);
369     code += "export enum ";
370     code += GetTypeName(enum_def);
371     code += " {\n";
372     for (auto it = enum_def.Vals().begin(); it != enum_def.Vals().end(); ++it) {
373       auto &ev = **it;
374       if (!ev.doc_comment.empty()) {
375         if (it != enum_def.Vals().begin()) { code += '\n'; }
376         GenDocComment(ev.doc_comment, code_ptr, "  ");
377       }
378 
379       // Generate mapping between EnumName: EnumValue(int)
380       if (reverse) {
381         code += "  '" + enum_def.ToString(ev) + "'";
382         code += " = ";
383         code += "'" + namer_.Variant(ev) + "'";
384       } else {
385         code += "  " + namer_.Variant(ev);
386         code += " = ";
387         // Unfortunately, because typescript does not support bigint enums,
388         // for 64-bit enums, we instead map the enum names to strings.
389         switch (enum_def.underlying_type.base_type) {
390           case BASE_TYPE_LONG:
391           case BASE_TYPE_ULONG: {
392             code += "'" + enum_def.ToString(ev) + "'";
393             break;
394           }
395           default: code += enum_def.ToString(ev);
396         }
397       }
398 
399       code += (it + 1) != enum_def.Vals().end() ? ",\n" : "\n";
400     }
401     code += "}";
402 
403     if (enum_def.is_union) {
404       code += GenUnionConvFunc(enum_def.underlying_type, imports);
405     }
406 
407     code += "\n";
408   }
409 
GenType(const Type & type)410   static std::string GenType(const Type &type) {
411     switch (type.base_type) {
412       case BASE_TYPE_BOOL:
413       case BASE_TYPE_CHAR: return "Int8";
414       case BASE_TYPE_UTYPE: return GenType(GetUnionUnderlyingType(type));
415       case BASE_TYPE_UCHAR: return "Uint8";
416       case BASE_TYPE_SHORT: return "Int16";
417       case BASE_TYPE_USHORT: return "Uint16";
418       case BASE_TYPE_INT: return "Int32";
419       case BASE_TYPE_UINT: return "Uint32";
420       case BASE_TYPE_LONG: return "Int64";
421       case BASE_TYPE_ULONG: return "Uint64";
422       case BASE_TYPE_FLOAT: return "Float32";
423       case BASE_TYPE_DOUBLE: return "Float64";
424       case BASE_TYPE_STRING: return "String";
425       case BASE_TYPE_VECTOR: return GenType(type.VectorType());
426       case BASE_TYPE_STRUCT: return type.struct_def->name;
427       default: return "flatbuffers.Table";
428     }
429   }
430 
GenGetter(const Type & type,const std::string & arguments)431   std::string GenGetter(const Type &type, const std::string &arguments) {
432     switch (type.base_type) {
433       case BASE_TYPE_STRING: return GenBBAccess() + ".__string" + arguments;
434       case BASE_TYPE_STRUCT: return GenBBAccess() + ".__struct" + arguments;
435       case BASE_TYPE_UNION:
436         if (!UnionHasStringType(*type.enum_def)) {
437           return GenBBAccess() + ".__union" + arguments;
438         }
439         return GenBBAccess() + ".__union_with_string" + arguments;
440       case BASE_TYPE_VECTOR: return GenGetter(type.VectorType(), arguments);
441       default: {
442         auto getter = GenBBAccess() + "." + "read" + GenType(type) + arguments;
443         if (type.base_type == BASE_TYPE_BOOL) { getter = "!!" + getter; }
444         return getter;
445       }
446     }
447   }
448 
GenBBAccess() const449   std::string GenBBAccess() const { return "this.bb!"; }
450 
GenDefaultValue(const FieldDef & field,import_set & imports)451   std::string GenDefaultValue(const FieldDef &field, import_set &imports) {
452     if (field.IsScalarOptional()) { return "null"; }
453 
454     const auto &value = field.value;
455     if (value.type.enum_def && value.type.base_type != BASE_TYPE_UNION &&
456         value.type.base_type != BASE_TYPE_VECTOR) {
457       switch (value.type.base_type) {
458         case BASE_TYPE_ARRAY: {
459           std::string ret = "[";
460           for (auto i = 0; i < value.type.fixed_length; ++i) {
461             std::string enum_name =
462                 AddImport(imports, *value.type.enum_def, *value.type.enum_def)
463                     .name;
464             std::string enum_value = namer_.Variant(
465                 *value.type.enum_def->FindByValue(value.constant));
466             ret += enum_name + "." + enum_value +
467                    (i < value.type.fixed_length - 1 ? ", " : "");
468           }
469           ret += "]";
470           return ret;
471         }
472         case BASE_TYPE_LONG:
473         case BASE_TYPE_ULONG: {
474           // If the value is an enum with a 64-bit base type, we have to just
475           // return the bigint value directly since typescript does not support
476           // enums with bigint backing types.
477           return "BigInt('" + value.constant + "')";
478         }
479         default: {
480           EnumVal *val = value.type.enum_def->FindByValue(value.constant);
481           if (val == nullptr)
482             val = const_cast<EnumVal *>(value.type.enum_def->MinValue());
483           return AddImport(imports, *value.type.enum_def, *value.type.enum_def)
484                      .name +
485                  "." + namer_.Variant(*val);
486         }
487       }
488     }
489 
490     switch (value.type.base_type) {
491       case BASE_TYPE_BOOL: return value.constant == "0" ? "false" : "true";
492 
493       case BASE_TYPE_STRING:
494       case BASE_TYPE_UNION:
495       case BASE_TYPE_STRUCT: {
496         return "null";
497       }
498 
499       case BASE_TYPE_ARRAY:
500       case BASE_TYPE_VECTOR: return "[]";
501 
502       case BASE_TYPE_LONG:
503       case BASE_TYPE_ULONG: {
504         return "BigInt('" + value.constant + "')";
505       }
506 
507       default: {
508         if (StringIsFlatbufferNan(value.constant)) {
509           return "NaN";
510         } else if (StringIsFlatbufferPositiveInfinity(value.constant)) {
511           return "Infinity";
512         } else if (StringIsFlatbufferNegativeInfinity(value.constant)) {
513           return "-Infinity";
514         }
515         return value.constant;
516       }
517     }
518   }
519 
GenTypeName(import_set & imports,const Definition & owner,const Type & type,bool input,bool allowNull=false)520   std::string GenTypeName(import_set &imports, const Definition &owner,
521                           const Type &type, bool input,
522                           bool allowNull = false) {
523     if (!input) {
524       if (IsString(type) || type.base_type == BASE_TYPE_STRUCT) {
525         std::string name;
526         if (IsString(type)) {
527           name = "string|Uint8Array";
528         } else {
529           name = AddImport(imports, owner, *type.struct_def).name;
530         }
531         return allowNull ? (name + "|null") : name;
532       }
533     }
534 
535     switch (type.base_type) {
536       case BASE_TYPE_BOOL: return allowNull ? "boolean|null" : "boolean";
537       case BASE_TYPE_LONG:
538       case BASE_TYPE_ULONG: return allowNull ? "bigint|null" : "bigint";
539       case BASE_TYPE_ARRAY: {
540         std::string name;
541         if (type.element == BASE_TYPE_LONG || type.element == BASE_TYPE_ULONG) {
542           name = "bigint[]";
543         } else if (type.element != BASE_TYPE_STRUCT) {
544           name = "number[]";
545         } else {
546           name = "any[]";
547           if (parser_.opts.generate_object_based_api) {
548             name = "(any|" +
549                    GetTypeName(*type.struct_def, /*object_api =*/true) + ")[]";
550           }
551         }
552 
553         return name + (allowNull ? "|null" : "");
554       }
555       default:
556         if (IsScalar(type.base_type)) {
557           if (type.enum_def) {
558             const auto enum_name =
559                 AddImport(imports, owner, *type.enum_def).name;
560             return allowNull ? (enum_name + "|null") : enum_name;
561           }
562           return allowNull ? "number|null" : "number";
563         }
564         return "flatbuffers.Offset";
565     }
566   }
567 
GetUnionUnderlyingType(const Type & type)568   static Type GetUnionUnderlyingType(const Type &type)
569   {
570     if (type.enum_def != nullptr &&
571         type.enum_def->underlying_type.base_type != type.base_type) {
572       return type.enum_def->underlying_type;
573     } else {
574         return Type(BASE_TYPE_UCHAR);
575     }
576   }
577 
GetUnderlyingVectorType(const Type & vector_type)578   static Type GetUnderlyingVectorType(const Type &vector_type)
579   {
580     return (vector_type.base_type == BASE_TYPE_UTYPE) ? GetUnionUnderlyingType(vector_type) : vector_type;
581   }
582 
583   // Returns the method name for use with add/put calls.
GenWriteMethod(const Type & type)584   std::string GenWriteMethod(const Type &type) {
585     // Forward to signed versions since unsigned versions don't exist
586     switch (type.base_type) {
587       case BASE_TYPE_UTYPE: return GenWriteMethod(GetUnionUnderlyingType(type));
588       case BASE_TYPE_UCHAR: return GenWriteMethod(Type(BASE_TYPE_CHAR));
589       case BASE_TYPE_USHORT: return GenWriteMethod(Type(BASE_TYPE_SHORT));
590       case BASE_TYPE_UINT: return GenWriteMethod(Type(BASE_TYPE_INT));
591       case BASE_TYPE_ULONG: return GenWriteMethod(Type(BASE_TYPE_LONG));
592       default: break;
593     }
594 
595     return IsScalar(type.base_type) ? namer_.Type(GenType(type))
596                                     : (IsStruct(type) ? "Struct" : "Offset");
597   }
598 
MaybeAdd(T value)599   template<typename T> static std::string MaybeAdd(T value) {
600     return value != 0 ? " + " + NumToString(value) : "";
601   }
602 
MaybeScale(T value)603   template<typename T> static std::string MaybeScale(T value) {
604     return value != 1 ? " * " + NumToString(value) : "";
605   }
606 
GenStructArgs(import_set & imports,const StructDef & struct_def,std::string * arguments,const std::string & nameprefix)607   void GenStructArgs(import_set &imports, const StructDef &struct_def,
608                      std::string *arguments, const std::string &nameprefix) {
609     for (auto it = struct_def.fields.vec.begin();
610          it != struct_def.fields.vec.end(); ++it) {
611       auto &field = **it;
612       if (IsStruct(field.value.type)) {
613         // Generate arguments for a struct inside a struct. To ensure names
614         // don't clash, and to make it obvious these arguments are constructing
615         // a nested struct, prefix the name with the field name.
616         GenStructArgs(imports, *field.value.type.struct_def, arguments,
617                       nameprefix + field.name + "_");
618       } else {
619         *arguments += ", " + nameprefix + field.name + ": " +
620                       GenTypeName(imports, field, field.value.type, true,
621                                   field.IsOptional());
622       }
623     }
624   }
625 
GenStructBody(const StructDef & struct_def,std::string * body,const std::string & nameprefix)626   void GenStructBody(const StructDef &struct_def, std::string *body,
627                      const std::string &nameprefix) {
628     *body += "  builder.prep(";
629     *body += NumToString(struct_def.minalign) + ", ";
630     *body += NumToString(struct_def.bytesize) + ");\n";
631 
632     for (auto it = struct_def.fields.vec.rbegin();
633          it != struct_def.fields.vec.rend(); ++it) {
634       auto &field = **it;
635       if (field.padding) {
636         *body += "  builder.pad(" + NumToString(field.padding) + ");\n";
637       }
638       if (IsStruct(field.value.type)) {
639         // Generate arguments for a struct inside a struct. To ensure names
640         // don't clash, and to make it obvious these arguments are constructing
641         // a nested struct, prefix the name with the field name.
642         GenStructBody(
643             *field.value.type.struct_def, body,
644             nameprefix.length() ? nameprefix + "_" + field.name : field.name);
645       } else {
646         auto element_type = field.value.type.element;
647 
648         if (field.value.type.base_type == BASE_TYPE_ARRAY) {
649           switch (field.value.type.element) {
650             case BASE_TYPE_STRUCT: {
651               std::string str_last_item_idx =
652                   NumToString(field.value.type.fixed_length - 1);
653               *body += "\n  for (let i = " + str_last_item_idx +
654                        "; i >= 0; --i" + ") {\n";
655 
656               std::string fname = nameprefix.length()
657                                       ? nameprefix + "_" + field.name
658                                       : field.name;
659 
660               *body += "    const item = " + fname + "?.[i];\n\n";
661 
662               if (parser_.opts.generate_object_based_api) {
663                 *body += "    if (item instanceof " +
664                          GetTypeName(*field.value.type.struct_def,
665                                      /*object_api =*/true) +
666                          ") {\n";
667                 *body += "      item.pack(builder);\n";
668                 *body += "      continue;\n";
669                 *body += "    }\n\n";
670               }
671 
672               std::string class_name =
673                   GetPrefixedName(*field.value.type.struct_def);
674               std::string pack_func_create_call =
675                   class_name + ".create" + class_name + "(builder,\n";
676               pack_func_create_call +=
677                   "    " +
678                   GenStructMemberValueTS(*field.value.type.struct_def, "item",
679                                          ",\n    ", false) +
680                   "\n  ";
681               *body += "    " + pack_func_create_call;
682               *body += "  );\n  }\n\n";
683 
684               break;
685             }
686             default: {
687               std::string str_last_item_idx =
688                   NumToString(field.value.type.fixed_length - 1);
689               std::string fname = nameprefix.length()
690                                       ? nameprefix + "_" + field.name
691                                       : field.name;
692 
693               *body += "\n  for (let i = " + str_last_item_idx +
694                        "; i >= 0; --i) {\n";
695               *body += "    builder.write";
696               *body += GenWriteMethod(
697                   static_cast<flatbuffers::Type>(field.value.type.element));
698               *body += "(";
699               *body += element_type == BASE_TYPE_BOOL ? "+" : "";
700 
701               if (element_type == BASE_TYPE_LONG ||
702                   element_type == BASE_TYPE_ULONG) {
703                 *body += "BigInt(" + fname + "?.[i] ?? 0));\n";
704               } else {
705                 *body += "(" + fname + "?.[i] ?? 0));\n\n";
706               }
707               *body += "  }\n\n";
708               break;
709             }
710           }
711         } else {
712           std::string fname =
713               nameprefix.length() ? nameprefix + "_" + field.name : field.name;
714 
715           *body += "  builder.write" + GenWriteMethod(field.value.type) + "(";
716           if (field.value.type.base_type == BASE_TYPE_BOOL) {
717             *body += "Number(Boolean(" + fname + ")));\n";
718             continue;
719           } else if (field.value.type.base_type == BASE_TYPE_LONG ||
720                      field.value.type.base_type == BASE_TYPE_ULONG) {
721             *body += "BigInt(" + fname + " ?? 0));\n";
722             continue;
723           }
724 
725           *body += fname + ");\n";
726         }
727       }
728     }
729   }
730 
GenerateNewExpression(const std::string & object_name)731   std::string GenerateNewExpression(const std::string &object_name) {
732     return "new " + namer_.Type(object_name) + "()";
733   }
734 
GenerateRootAccessor(StructDef & struct_def,std::string * code_ptr,std::string & code,const std::string & object_name,bool size_prefixed)735   void GenerateRootAccessor(StructDef &struct_def, std::string *code_ptr,
736                             std::string &code, const std::string &object_name,
737                             bool size_prefixed) {
738     if (!struct_def.fixed) {
739       GenDocComment(code_ptr);
740       std::string sizePrefixed("SizePrefixed");
741       code += "static get" + (size_prefixed ? sizePrefixed : "") + "Root" +
742               GetPrefixedName(struct_def, "As");
743       code += "(bb:flatbuffers.ByteBuffer, obj?:" + object_name +
744               "):" + object_name + " {\n";
745       if (size_prefixed) {
746         code +=
747             "  bb.setPosition(bb.position() + "
748             "flatbuffers.SIZE_PREFIX_LENGTH);\n";
749       }
750       code += "  return (obj || " + GenerateNewExpression(object_name);
751       code += ").__init(bb.readInt32(bb.position()) + bb.position(), bb);\n";
752       code += "}\n\n";
753     }
754   }
755 
GenerateFinisher(StructDef & struct_def,std::string * code_ptr,std::string & code,bool size_prefixed)756   void GenerateFinisher(StructDef &struct_def, std::string *code_ptr,
757                         std::string &code, bool size_prefixed) {
758     if (parser_.root_struct_def_ == &struct_def) {
759       std::string sizePrefixed("SizePrefixed");
760       GenDocComment(code_ptr);
761 
762       code += "static finish" + (size_prefixed ? sizePrefixed : "") +
763               GetPrefixedName(struct_def) + "Buffer";
764       code += "(builder:flatbuffers.Builder, offset:flatbuffers.Offset) {\n";
765       code += "  builder.finish(offset";
766       if (!parser_.file_identifier_.empty()) {
767         code += ", '" + parser_.file_identifier_ + "'";
768       }
769       if (size_prefixed) {
770         if (parser_.file_identifier_.empty()) { code += ", undefined"; }
771         code += ", true";
772       }
773       code += ");\n";
774       code += "}\n\n";
775     }
776   }
777 
UnionHasStringType(const EnumDef & union_enum)778   bool UnionHasStringType(const EnumDef &union_enum) {
779     return std::any_of(union_enum.Vals().begin(), union_enum.Vals().end(),
780                        [](const EnumVal *ev) {
781                          return !ev->IsZero() && IsString(ev->union_type);
782                        });
783   }
784 
GenUnionGenericTypeTS(const EnumDef & union_enum)785   std::string GenUnionGenericTypeTS(const EnumDef &union_enum) {
786     // TODO: make it work without any
787     // return std::string("T") + (UnionHasStringType(union_enum) ? "|string" :
788     // "");
789     return std::string("any") +
790            (UnionHasStringType(union_enum) ? "|string" : "");
791   }
792 
GenUnionTypeTS(const EnumDef & union_enum,import_set & imports)793   std::string GenUnionTypeTS(const EnumDef &union_enum, import_set &imports) {
794     std::string ret;
795     std::set<std::string> type_list;
796 
797     for (auto it = union_enum.Vals().begin(); it != union_enum.Vals().end();
798          ++it) {
799       const auto &ev = **it;
800       if (ev.IsZero()) { continue; }
801 
802       std::string type = "";
803       if (IsString(ev.union_type)) {
804         type = "string";  // no need to wrap string type in namespace
805       } else if (ev.union_type.base_type == BASE_TYPE_STRUCT) {
806         type = AddImport(imports, union_enum, *ev.union_type.struct_def).name;
807       } else {
808         FLATBUFFERS_ASSERT(false);
809       }
810       type_list.insert(type);
811     }
812 
813     for (auto it = type_list.begin(); it != type_list.end(); ++it) {
814       ret += *it + ((std::next(it) == type_list.end()) ? "" : "|");
815     }
816 
817     return ret;
818   }
819 
CheckIfNameClashes(const import_set & imports,const std::string & name)820   static bool CheckIfNameClashes(const import_set &imports,
821                                  const std::string &name) {
822     // TODO: this would be better as a hashset.
823     for (auto it = imports.begin(); it != imports.end(); it++) {
824       if (it->second.name == name) { return true; }
825     }
826     return false;
827   }
828 
GenSymbolExpression(const StructDef & struct_def,const bool has_name_clash,const std::string & import_name,const std::string & name,const std::string & object_name)829   std::string GenSymbolExpression(const StructDef &struct_def,
830                                   const bool has_name_clash,
831                                   const std::string &import_name,
832                                   const std::string &name,
833                                   const std::string &object_name) {
834     std::string symbols_expression;
835 
836     if (has_name_clash) {
837       // We have a name clash
838       symbols_expression += import_name + " as " + name;
839 
840       if (parser_.opts.generate_object_based_api) {
841         symbols_expression += ", " +
842                               GetTypeName(struct_def, /*object_api =*/true) +
843                               " as " + object_name;
844       }
845     } else {
846       // No name clash, use the provided name
847       symbols_expression += name;
848 
849       if (parser_.opts.generate_object_based_api) {
850         symbols_expression += ", " + object_name;
851       }
852     }
853 
854     return symbols_expression;
855   }
856 
GenSymbolExpression(const EnumDef & enum_def,const bool has_name_clash,const std::string & import_name,const std::string & name,const std::string &)857   std::string GenSymbolExpression(const EnumDef &enum_def,
858                                   const bool has_name_clash,
859                                   const std::string &import_name,
860                                   const std::string &name,
861                                   const std::string &) {
862     std::string symbols_expression;
863     if (has_name_clash) {
864       symbols_expression += import_name + " as " + name;
865     } else {
866       symbols_expression += name;
867     }
868 
869     if (enum_def.is_union) {
870       symbols_expression += (", " + namer_.Function("unionTo" + name));
871       symbols_expression += (", " + namer_.Function("unionListTo" + name));
872     }
873 
874     return symbols_expression;
875   }
876 
877   template<typename DefinitionT>
AddImport(import_set & imports,const Definition & dependent,const DefinitionT & dependency)878   ImportDefinition AddImport(import_set &imports, const Definition &dependent,
879                              const DefinitionT &dependency) {
880     // The unique name of the dependency, fully qualified in its namespace.
881     const std::string unique_name = GetTypeName(
882         dependency, /*object_api = */ false, /*force_ns_wrap=*/true);
883 
884     // Look if we have already added this import and return its name if found.
885     const auto import_pair = imports.find(unique_name);
886     if (import_pair != imports.end()) { return import_pair->second; }
887 
888     // Check if this name would have a name clash with another type. Just use
889     // the "base" name (properly escaped) without any namespacing applied.
890     const std::string import_name = GetTypeName(dependency);
891     const bool has_name_clash = CheckIfNameClashes(imports, import_name);
892 
893     // If we have a name clash, use the unique name, otherwise use simple name.
894     std::string name = has_name_clash ? unique_name : import_name;
895 
896     const std::string object_name =
897         GetTypeName(dependency, /*object_api=*/true, has_name_clash);
898 
899     const std::string symbols_expression = GenSymbolExpression(
900         dependency, has_name_clash, import_name, name, object_name);
901 
902     std::string bare_file_path;
903     std::string rel_file_path;
904     const auto &dep_comps = dependent.defined_namespace->components;
905     for (size_t i = 0; i < dep_comps.size(); i++) {
906       rel_file_path += i == 0 ? ".." : (kPathSeparator + std::string(".."));
907     }
908     if (dep_comps.size() == 0) { rel_file_path += "."; }
909 
910     bare_file_path +=
911         kPathSeparator +
912         namer_.Directories(dependency.defined_namespace->components,
913                            SkipDir::OutputPath) +
914         namer_.File(dependency, SkipFile::SuffixAndExtension);
915     rel_file_path += bare_file_path;
916 
917     ImportDefinition import;
918     import.name = name;
919     import.object_name = object_name;
920     import.bare_file_path = bare_file_path;
921     import.rel_file_path = rel_file_path;
922     std::string import_extension = parser_.opts.ts_no_import_ext ? "" : ".js";
923     import.import_statement = "import { " + symbols_expression + " } from '" +
924                               rel_file_path + import_extension + "';";
925     import.export_statement = "export { " + symbols_expression + " } from '." +
926                               bare_file_path + import_extension + "';";
927     import.dependency = &dependency;
928     import.dependent = &dependent;
929 
930     imports.insert(std::make_pair(unique_name, import));
931 
932     return import;
933   }
934 
AddImport(import_set & imports,std::string import_name,std::string fileName)935   void AddImport(import_set &imports, std::string import_name,
936                  std::string fileName) {
937     ImportDefinition import;
938     import.name = import_name;
939     import.import_statement =
940         "import " + import_name + " from '" + fileName + "';";
941     imports.insert(std::make_pair(import_name, import));
942   }
943 
944   // Generate a TS union type based on a union's enum
GenObjApiUnionTypeTS(import_set & imports,const StructDef & dependent,const IDLOptions &,const EnumDef & union_enum)945   std::string GenObjApiUnionTypeTS(import_set &imports,
946                                    const StructDef &dependent,
947                                    const IDLOptions &,
948                                    const EnumDef &union_enum) {
949     std::string ret = "";
950     std::set<std::string> type_list;
951 
952     for (auto it = union_enum.Vals().begin(); it != union_enum.Vals().end();
953          ++it) {
954       const auto &ev = **it;
955       if (ev.IsZero()) { continue; }
956 
957       std::string type = "";
958       if (IsString(ev.union_type)) {
959         type = "string";  // no need to wrap string type in namespace
960       } else if (ev.union_type.base_type == BASE_TYPE_STRUCT) {
961         type = AddImport(imports, dependent, *ev.union_type.struct_def)
962                    .object_name;
963       } else {
964         FLATBUFFERS_ASSERT(false);
965       }
966       type_list.insert(type);
967     }
968 
969     size_t totalPrinted = 0;
970     for (auto it = type_list.begin(); it != type_list.end(); ++it) {
971       ++totalPrinted;
972       ret += *it + ((totalPrinted == type_list.size()) ? "" : "|");
973     }
974 
975     return ret;
976   }
977 
GenUnionConvFuncName(const EnumDef & enum_def)978   std::string GenUnionConvFuncName(const EnumDef &enum_def) {
979     return namer_.Function("unionTo", enum_def);
980   }
981 
GenUnionListConvFuncName(const EnumDef & enum_def)982   std::string GenUnionListConvFuncName(const EnumDef &enum_def) {
983     return namer_.Function("unionListTo", enum_def);
984   }
985 
GenUnionConvFunc(const Type & union_type,import_set & imports)986   std::string GenUnionConvFunc(const Type &union_type, import_set &imports) {
987     if (union_type.enum_def) {
988       const auto &enum_def = *union_type.enum_def;
989 
990       const auto valid_union_type = GenUnionTypeTS(enum_def, imports);
991       const auto valid_union_type_with_null = valid_union_type + "|null";
992 
993       auto ret = "\n\nexport function " + GenUnionConvFuncName(enum_def) +
994                  "(\n  type: " + GetTypeName(enum_def) +
995                  ",\n  accessor: (obj:" + valid_union_type + ") => " +
996                  valid_union_type_with_null +
997                  "\n): " + valid_union_type_with_null + " {\n";
998 
999       const auto enum_type = AddImport(imports, enum_def, enum_def).name;
1000 
1001       const auto union_enum_loop = [&](const std::string &accessor_str) {
1002         ret += "  switch(" + enum_type + "[type]) {\n";
1003         ret += "    case 'NONE': return null; \n";
1004 
1005         for (auto it = enum_def.Vals().begin(); it != enum_def.Vals().end();
1006              ++it) {
1007           const auto &ev = **it;
1008           if (ev.IsZero()) { continue; }
1009 
1010           ret += "    case '" + namer_.Variant(ev) + "': ";
1011 
1012           if (IsString(ev.union_type)) {
1013             ret += "return " + accessor_str + "'') as string;";
1014           } else if (ev.union_type.base_type == BASE_TYPE_STRUCT) {
1015             const auto type =
1016                 AddImport(imports, enum_def, *ev.union_type.struct_def).name;
1017             ret += "return " + accessor_str + "new " + type + "())! as " +
1018                    type + ";";
1019           } else {
1020             FLATBUFFERS_ASSERT(false);
1021           }
1022           ret += "\n";
1023         }
1024 
1025         ret += "    default: return null;\n";
1026         ret += "  }\n";
1027       };
1028 
1029       union_enum_loop("accessor(");
1030       ret += "}";
1031 
1032       ret += "\n\nexport function " + GenUnionListConvFuncName(enum_def) +
1033              "(\n  type: " + GetTypeName(enum_def) +
1034              ", \n  accessor: (index: number, obj:" + valid_union_type +
1035              ") => " + valid_union_type_with_null +
1036              ", \n  index: number\n): " + valid_union_type_with_null + " {\n";
1037       union_enum_loop("accessor(index, ");
1038       ret += "}";
1039 
1040       return ret;
1041     }
1042     FLATBUFFERS_ASSERT(0);
1043     return "";
1044   }
1045 
1046   // Used for generating a short function that returns the correct class
1047   // based on union enum type. Assume the context is inside the non object api
1048   // type
GenUnionValTS(import_set & imports,const StructDef & dependent,const std::string & field_name,const Type & union_type,const bool is_array=false)1049   std::string GenUnionValTS(import_set &imports, const StructDef &dependent,
1050                             const std::string &field_name,
1051                             const Type &union_type,
1052                             const bool is_array = false) {
1053     if (union_type.enum_def) {
1054       const auto &enum_def = *union_type.enum_def;
1055       const auto enum_type = AddImport(imports, dependent, enum_def).name;
1056       const std::string union_accessor = "this." + field_name;
1057 
1058       const auto union_has_string = UnionHasStringType(enum_def);
1059       const auto field_binded_method = "this." + field_name + ".bind(this)";
1060 
1061       std::string ret;
1062 
1063       if (!is_array) {
1064         const auto conversion_function = GenUnionConvFuncName(enum_def);
1065 
1066         ret = "(() => {\n";
1067         ret += "      const temp = " + conversion_function + "(this." +
1068                namer_.Method(field_name, "Type") + "(), " +
1069                field_binded_method + ");\n";
1070         ret += "      if(temp === null) { return null; }\n";
1071         ret += union_has_string
1072                    ? "      if(typeof temp === 'string') { return temp; }\n"
1073                    : "";
1074         ret += "      return temp.unpack()\n";
1075         ret += "  })()";
1076       } else {
1077         const auto conversion_function = GenUnionListConvFuncName(enum_def);
1078 
1079         ret = "(() => {\n";
1080         ret += "    const ret: (" +
1081                GenObjApiUnionTypeTS(imports, *union_type.struct_def,
1082                                     parser_.opts, *union_type.enum_def) +
1083                ")[] = [];\n";
1084         ret += "    for(let targetEnumIndex = 0; targetEnumIndex < this." +
1085                namer_.Method(field_name, "TypeLength") + "()" +
1086                "; "
1087                "++targetEnumIndex) {\n";
1088         ret += "      const targetEnum = this." +
1089                namer_.Method(field_name, "Type") + "(targetEnumIndex);\n";
1090         ret += "      if(targetEnum === null || " + enum_type +
1091                "[targetEnum!] === 'NONE') { "
1092                "continue; }\n\n";
1093         ret += "      const temp = " + conversion_function + "(targetEnum, " +
1094                field_binded_method + ", targetEnumIndex);\n";
1095         ret += "      if(temp === null) { continue; }\n";
1096         ret += union_has_string ? "      if(typeof temp === 'string') { "
1097                                   "ret.push(temp); continue; }\n"
1098                                 : "";
1099         ret += "      ret.push(temp.unpack());\n";
1100         ret += "    }\n";
1101         ret += "    return ret;\n";
1102         ret += "  })()";
1103       }
1104 
1105       return ret;
1106     }
1107 
1108     FLATBUFFERS_ASSERT(0);
1109     return "";
1110   }
1111 
GenNullCheckConditional(const std::string & nullCheckVar,const std::string & trueVal,const std::string & falseVal="null")1112   static std::string GenNullCheckConditional(
1113       const std::string &nullCheckVar, const std::string &trueVal,
1114       const std::string &falseVal = "null") {
1115     return "(" + nullCheckVar + " !== null ? " + trueVal + " : " + falseVal +
1116            ")";
1117   }
1118 
GenStructMemberValueTS(const StructDef & struct_def,const std::string & prefix,const std::string & delimiter,const bool nullCheck=true)1119   std::string GenStructMemberValueTS(const StructDef &struct_def,
1120                                      const std::string &prefix,
1121                                      const std::string &delimiter,
1122                                      const bool nullCheck = true) {
1123     std::string ret;
1124     for (auto it = struct_def.fields.vec.begin();
1125          it != struct_def.fields.vec.end(); ++it) {
1126       auto &field = **it;
1127 
1128       auto curr_member_accessor = prefix + "." + namer_.Method(field);
1129       if (prefix != "this") {
1130         curr_member_accessor = prefix + "?." + namer_.Method(field);
1131       }
1132       if (IsStruct(field.value.type)) {
1133         ret += GenStructMemberValueTS(*field.value.type.struct_def,
1134                                       curr_member_accessor, delimiter);
1135       } else {
1136         if (nullCheck) {
1137           std::string nullValue = "0";
1138           if (field.value.type.base_type == BASE_TYPE_BOOL) {
1139             nullValue = "false";
1140           } else if (field.value.type.base_type == BASE_TYPE_LONG ||
1141                      field.value.type.base_type == BASE_TYPE_ULONG) {
1142             nullValue = "BigInt(0)";
1143           } else if (field.value.type.base_type == BASE_TYPE_ARRAY) {
1144             nullValue = "[]";
1145           }
1146           ret += "(" + curr_member_accessor + " ?? " + nullValue + ")";
1147         } else {
1148           ret += curr_member_accessor;
1149         }
1150       }
1151 
1152       if (std::next(it) != struct_def.fields.vec.end()) { ret += delimiter; }
1153     }
1154 
1155     return ret;
1156   }
1157 
GenObjApi(const Parser & parser,StructDef & struct_def,std::string & obj_api_unpack_func,std::string & obj_api_class,import_set & imports)1158   void GenObjApi(const Parser &parser, StructDef &struct_def,
1159                  std::string &obj_api_unpack_func, std::string &obj_api_class,
1160                  import_set &imports) {
1161     const auto class_name = GetTypeName(struct_def, /*object_api=*/true);
1162 
1163     std::string unpack_func = "\nunpack(): " + class_name +
1164                               " {\n  return new " + class_name + "(" +
1165                               (struct_def.fields.vec.empty() ? "" : "\n");
1166     std::string unpack_to_func = "\nunpackTo(_o: " + class_name + "): void {" +
1167                                  +(struct_def.fields.vec.empty() ? "" : "\n");
1168 
1169     std::string constructor_func = "constructor(";
1170     constructor_func += (struct_def.fields.vec.empty() ? "" : "\n");
1171 
1172     const auto has_create =
1173         struct_def.fixed || CanCreateFactoryMethod(struct_def);
1174 
1175     std::string pack_func_prototype =
1176         "\npack(builder:flatbuffers.Builder): flatbuffers.Offset {\n";
1177 
1178     std::string pack_func_offset_decl;
1179     std::string pack_func_create_call;
1180 
1181     const auto struct_name = AddImport(imports, struct_def, struct_def).name;
1182 
1183     if (has_create) {
1184       pack_func_create_call = "  return " + struct_name + ".create" +
1185                               GetPrefixedName(struct_def) + "(builder" +
1186                               (struct_def.fields.vec.empty() ? "" : ",\n    ");
1187     } else {
1188       pack_func_create_call = "  " + struct_name + ".start" +
1189                               GetPrefixedName(struct_def) + "(builder);\n";
1190     }
1191 
1192     if (struct_def.fixed) {
1193       // when packing struct, nested struct's members instead of the struct's
1194       // offset are used
1195       pack_func_create_call +=
1196           GenStructMemberValueTS(struct_def, "this", ",\n    ", false) + "\n  ";
1197     }
1198 
1199     for (auto it = struct_def.fields.vec.begin();
1200          it != struct_def.fields.vec.end(); ++it) {
1201       auto &field = **it;
1202       if (field.deprecated) continue;
1203 
1204       const auto field_method = namer_.Method(field);
1205       const auto field_field = namer_.Field(field);
1206       const std::string field_binded_method =
1207           "this." + field_method + ".bind(this)";
1208 
1209       std::string field_val;
1210       std::string field_type;
1211       // a string that declares a variable containing the
1212       // offset for things that can't be generated inline
1213       // empty otw
1214       std::string field_offset_decl;
1215       // a string that contains values for things that can be created inline or
1216       // the variable name from field_offset_decl
1217       std::string field_offset_val;
1218       const auto field_default_val = GenDefaultValue(field, imports);
1219 
1220       // Emit a scalar field
1221       const auto is_string = IsString(field.value.type);
1222       if (IsScalar(field.value.type.base_type) || is_string) {
1223         const auto has_null_default = is_string || HasNullDefault(field);
1224 
1225         field_type += GenTypeName(imports, field, field.value.type, false,
1226                                   has_null_default);
1227         field_val = "this." + namer_.Method(field) + "()";
1228 
1229         if (field.value.type.base_type != BASE_TYPE_STRING) {
1230           field_offset_val = "this." + namer_.Field(field);
1231         } else {
1232           field_offset_decl = GenNullCheckConditional(
1233               "this." + namer_.Field(field),
1234               "builder.createString(this." + field_field + "!)", "0");
1235         }
1236       }
1237 
1238       // Emit an object field
1239       else {
1240         auto is_vector = false;
1241         switch (field.value.type.base_type) {
1242           case BASE_TYPE_STRUCT: {
1243             const auto &sd = *field.value.type.struct_def;
1244             field_type += AddImport(imports, struct_def, sd).object_name;
1245 
1246             const std::string field_accessor =
1247                 "this." + namer_.Method(field) + "()";
1248             field_val = GenNullCheckConditional(field_accessor,
1249                                                 field_accessor + "!.unpack()");
1250             auto packing = GenNullCheckConditional(
1251                 "this." + field_field,
1252                 "this." + field_field + "!.pack(builder)", "0");
1253 
1254             if (sd.fixed) {
1255               field_offset_val = std::move(packing);
1256             } else {
1257               field_offset_decl = std::move(packing);
1258             }
1259 
1260             break;
1261           }
1262 
1263           case BASE_TYPE_ARRAY: {
1264             auto vectortype = field.value.type.VectorType();
1265             auto vectortypename =
1266                 GenTypeName(imports, struct_def, vectortype, false);
1267             is_vector = true;
1268 
1269             field_type = "(";
1270 
1271             switch (vectortype.base_type) {
1272               case BASE_TYPE_STRUCT: {
1273                 const auto &sd = *field.value.type.struct_def;
1274                 const auto field_type_name =
1275                     GetTypeName(sd, /*object_api=*/true);
1276                 field_type += field_type_name;
1277                 field_type += ")[]";
1278 
1279                 field_val = GenBBAccess() + ".createObjList<" + vectortypename +
1280                             ", " + field_type_name + ">(" +
1281                             field_binded_method + ", " +
1282                             NumToString(field.value.type.fixed_length) + ")";
1283 
1284                 if (sd.fixed) {
1285                   field_offset_decl =
1286                       "builder.createStructOffsetList(this." + field_field +
1287                       ", " + AddImport(imports, struct_def, struct_def).name +
1288                       "." + namer_.Method("start", field, "Vector") + ")";
1289                 } else {
1290                   field_offset_decl =
1291                       AddImport(imports, struct_def, struct_def).name + "." +
1292                       namer_.Method("create", field, "Vector") +
1293                       "(builder, builder.createObjectOffsetList(" + "this." +
1294                       field_field + "))";
1295                 }
1296 
1297                 break;
1298               }
1299 
1300               case BASE_TYPE_STRING: {
1301                 field_type += "string)[]";
1302                 field_val = GenBBAccess() + ".createScalarList<string>(" +
1303                             field_binded_method + ", this." +
1304                             namer_.Field(field, "Length") + "())";
1305                 field_offset_decl =
1306                     AddImport(imports, struct_def, struct_def).name + "." +
1307                     namer_.Method("create", field, "Vector") +
1308                     "(builder, builder.createObjectOffsetList(" + "this." +
1309                     namer_.Field(field) + "))";
1310                 break;
1311               }
1312 
1313               case BASE_TYPE_UNION: {
1314                 field_type += GenObjApiUnionTypeTS(
1315                     imports, struct_def, parser.opts, *(vectortype.enum_def));
1316                 field_type += ")[]";
1317                 field_val = GenUnionValTS(imports, struct_def, field_method,
1318                                           vectortype, true);
1319 
1320                 field_offset_decl =
1321                     AddImport(imports, struct_def, struct_def).name + "." +
1322                     namer_.Method("create", field, "Vector") +
1323                     "(builder, builder.createObjectOffsetList(" + "this." +
1324                     namer_.Field(field) + "))";
1325 
1326                 break;
1327               }
1328               default: {
1329                 if (vectortype.enum_def) {
1330                   field_type += GenTypeName(imports, struct_def, vectortype,
1331                                             false, HasNullDefault(field));
1332                 } else {
1333                   field_type += vectortypename;
1334                 }
1335                 field_type += ")[]";
1336                 field_val = GenBBAccess() + ".createScalarList<" +
1337                             vectortypename + ">(" + field_binded_method + ", " +
1338                             NumToString(field.value.type.fixed_length) + ")";
1339 
1340                 field_offset_decl =
1341                     AddImport(imports, struct_def, struct_def).name + "." +
1342                     namer_.Method("create", field, "Vector") +
1343                     "(builder, this." + field_field + ")";
1344 
1345                 break;
1346               }
1347             }
1348 
1349             break;
1350           }
1351 
1352           case BASE_TYPE_VECTOR: {
1353             auto vectortype = field.value.type.VectorType();
1354             auto vectortypename =
1355                 GenTypeName(imports, struct_def, vectortype, false);
1356             is_vector = true;
1357 
1358             field_type = "(";
1359 
1360             switch (vectortype.base_type) {
1361               case BASE_TYPE_STRUCT: {
1362                 const auto &sd = *field.value.type.struct_def;
1363                 const auto field_type_name =
1364                     GetTypeName(sd, /*object_api=*/true);
1365                 field_type += field_type_name;
1366                 field_type += ")[]";
1367 
1368                 field_val = GenBBAccess() + ".createObjList<" + vectortypename +
1369                             ", " + field_type_name + ">(" +
1370                             field_binded_method + ", this." +
1371                             namer_.Method(field, "Length") + "())";
1372 
1373                 if (sd.fixed) {
1374                   field_offset_decl =
1375                       "builder.createStructOffsetList(this." + field_field +
1376                       ", " + AddImport(imports, struct_def, struct_def).name +
1377                       "." + namer_.Method("start", field, "Vector") + ")";
1378                 } else {
1379                   field_offset_decl =
1380                       AddImport(imports, struct_def, struct_def).name + "." +
1381                       namer_.Method("create", field, "Vector") +
1382                       "(builder, builder.createObjectOffsetList(" + "this." +
1383                       field_field + "))";
1384                 }
1385 
1386                 break;
1387               }
1388 
1389               case BASE_TYPE_STRING: {
1390                 field_type += "string)[]";
1391                 field_val = GenBBAccess() + ".createScalarList<string>(" +
1392                             field_binded_method + ", this." +
1393                             namer_.Field(field, "Length") + "())";
1394                 field_offset_decl =
1395                     AddImport(imports, struct_def, struct_def).name + "." +
1396                     namer_.Method("create", field, "Vector") +
1397                     "(builder, builder.createObjectOffsetList(" + "this." +
1398                     namer_.Field(field) + "))";
1399                 break;
1400               }
1401 
1402               case BASE_TYPE_UNION: {
1403                 field_type += GenObjApiUnionTypeTS(
1404                     imports, struct_def, parser.opts, *(vectortype.enum_def));
1405                 field_type += ")[]";
1406                 field_val = GenUnionValTS(imports, struct_def, field_method,
1407                                           vectortype, true);
1408 
1409                 field_offset_decl =
1410                     AddImport(imports, struct_def, struct_def).name + "." +
1411                     namer_.Method("create", field, "Vector") +
1412                     "(builder, builder.createObjectOffsetList(" + "this." +
1413                     namer_.Field(field) + "))";
1414 
1415                 break;
1416               }
1417               default: {
1418                 if (vectortype.enum_def) {
1419                   field_type += GenTypeName(imports, struct_def, vectortype,
1420                                             false, HasNullDefault(field));
1421                 } else {
1422                   field_type += vectortypename;
1423                 }
1424                 field_type += ")[]";
1425                 field_val = GenBBAccess() + ".createScalarList<" +
1426                             vectortypename + ">(" + field_binded_method +
1427                             ", this." + namer_.Method(field, "Length") + "())";
1428 
1429                 field_offset_decl =
1430                     AddImport(imports, struct_def, struct_def).name + "." +
1431                     namer_.Method("create", field, "Vector") +
1432                     "(builder, this." + field_field + ")";
1433 
1434                 break;
1435               }
1436             }
1437 
1438             break;
1439           }
1440 
1441           case BASE_TYPE_UNION: {
1442             field_type += GenObjApiUnionTypeTS(imports, struct_def, parser.opts,
1443                                                *(field.value.type.enum_def));
1444 
1445             field_val = GenUnionValTS(imports, struct_def, field_method,
1446                                       field.value.type);
1447             field_offset_decl =
1448                 "builder.createObjectOffset(this." + field_field + ")";
1449             break;
1450           }
1451 
1452           default: FLATBUFFERS_ASSERT(0); break;
1453         }
1454 
1455         // length 0 vector is simply empty instead of null
1456         field_type += is_vector ? "" : "|null";
1457       }
1458 
1459       if (!field_offset_decl.empty()) {
1460         field_offset_decl =
1461             "  const " + field_field + " = " + field_offset_decl + ";";
1462       }
1463       if (field_offset_val.empty()) { field_offset_val = field_field; }
1464 
1465       unpack_func += "    " + field_val;
1466       unpack_to_func += "  _o." + field_field + " = " + field_val + ";";
1467 
1468       // FIXME: if field_type and field_field are identical, then
1469       // this generates invalid typescript.
1470       constructor_func += "  public " + field_field + ": " + field_type +
1471                           " = " + field_default_val;
1472 
1473       if (!struct_def.fixed) {
1474         if (!field_offset_decl.empty()) {
1475           pack_func_offset_decl += field_offset_decl + "\n";
1476         }
1477 
1478         if (has_create) {
1479           pack_func_create_call += field_offset_val;
1480         } else {
1481           if (field.IsScalarOptional()) {
1482             pack_func_create_call +=
1483                 "  if (" + field_offset_val + " !== null)\n  ";
1484           }
1485           pack_func_create_call += "  " + struct_name + "." +
1486                                    namer_.Method("add", field) + "(builder, " +
1487                                    field_offset_val + ");\n";
1488         }
1489       }
1490 
1491       if (std::next(it) != struct_def.fields.vec.end()) {
1492         constructor_func += ",\n";
1493 
1494         if (!struct_def.fixed && has_create) {
1495           pack_func_create_call += ",\n    ";
1496         }
1497 
1498         unpack_func += ",\n";
1499         unpack_to_func += "\n";
1500       } else {
1501         constructor_func += "\n";
1502         if (!struct_def.fixed) {
1503           pack_func_offset_decl += (pack_func_offset_decl.empty() ? "" : "\n");
1504           pack_func_create_call += "\n  ";
1505         }
1506 
1507         unpack_func += "\n  ";
1508         unpack_to_func += "\n";
1509       }
1510     }
1511 
1512     constructor_func += "){}\n\n";
1513 
1514     if (has_create) {
1515       pack_func_create_call += ");";
1516     } else {
1517       pack_func_create_call += "return " + struct_name + ".end" +
1518                                GetPrefixedName(struct_def) + "(builder);";
1519     }
1520     obj_api_class = "\n";
1521     obj_api_class += "export class ";
1522     obj_api_class += GetTypeName(struct_def, /*object_api=*/true);
1523     obj_api_class += " implements flatbuffers.IGeneratedObject {\n";
1524     obj_api_class += constructor_func;
1525     obj_api_class += pack_func_prototype + pack_func_offset_decl +
1526                      pack_func_create_call + "\n}";
1527 
1528     obj_api_class += "\n}\n";
1529 
1530     unpack_func += ");\n}";
1531     unpack_to_func += "}\n";
1532 
1533     obj_api_unpack_func = unpack_func + "\n\n" + unpack_to_func;
1534   }
1535 
CanCreateFactoryMethod(const StructDef & struct_def)1536   static bool CanCreateFactoryMethod(const StructDef &struct_def) {
1537     // to preserve backwards compatibility, we allow the first field to be a
1538     // struct
1539     return struct_def.fields.vec.size() < 2 ||
1540            std::all_of(std::begin(struct_def.fields.vec) + 1,
1541                        std::end(struct_def.fields.vec),
1542                        [](const FieldDef *f) -> bool {
1543                          FLATBUFFERS_ASSERT(f != nullptr);
1544                          return f->value.type.base_type != BASE_TYPE_STRUCT;
1545                        });
1546   }
1547 
1548   // Generate an accessor struct with constructor for a flatbuffers struct.
GenStruct(const Parser & parser,StructDef & struct_def,std::string * code_ptr,import_set & imports)1549   void GenStruct(const Parser &parser, StructDef &struct_def,
1550                  std::string *code_ptr, import_set &imports) {
1551     if (struct_def.generated) return;
1552     std::string &code = *code_ptr;
1553 
1554     // Special case for the root struct, since no one will necessarily reference
1555     // it, we have to explicitly add it to the import list.
1556     if (&struct_def == parser_.root_struct_def_) {
1557       AddImport(imports, struct_def, struct_def);
1558     }
1559 
1560     const std::string object_name = GetTypeName(struct_def);
1561     const std::string object_api_name = GetTypeName(struct_def, true);
1562 
1563     // Emit constructor
1564     GenDocComment(struct_def.doc_comment, code_ptr);
1565     code += "export class ";
1566     code += object_name;
1567     if (parser.opts.generate_object_based_api)
1568       code += " implements flatbuffers.IUnpackableObject<" + object_api_name +
1569               "> {\n";
1570     else
1571       code += " {\n";
1572     code += "  bb: flatbuffers.ByteBuffer|null = null;\n";
1573     code += "  bb_pos = 0;\n";
1574 
1575     // Generate the __init method that sets the field in a pre-existing
1576     // accessor object. This is to allow object reuse.
1577     code +=
1578         "  __init(i:number, bb:flatbuffers.ByteBuffer):" + object_name + " {\n";
1579     code += "  this.bb_pos = i;\n";
1580     code += "  this.bb = bb;\n";
1581     code += "  return this;\n";
1582     code += "}\n\n";
1583 
1584     // Generate special accessors for the table that when used as the root of a
1585     // FlatBuffer
1586     GenerateRootAccessor(struct_def, code_ptr, code, object_name, false);
1587     GenerateRootAccessor(struct_def, code_ptr, code, object_name, true);
1588 
1589     // Generate the identifier check method
1590     if (!struct_def.fixed && parser_.root_struct_def_ == &struct_def &&
1591         !parser_.file_identifier_.empty()) {
1592       GenDocComment(code_ptr);
1593       code +=
1594           "static bufferHasIdentifier(bb:flatbuffers.ByteBuffer):boolean "
1595           "{\n";
1596       code += "  return bb.__has_identifier('" + parser_.file_identifier_;
1597       code += "');\n}\n\n";
1598     }
1599 
1600     // Emit field accessors
1601     for (auto it = struct_def.fields.vec.begin();
1602          it != struct_def.fields.vec.end(); ++it) {
1603       auto &field = **it;
1604       if (field.deprecated) continue;
1605       std::string offset_prefix = "";
1606 
1607       if (field.value.type.base_type == BASE_TYPE_ARRAY) {
1608         offset_prefix = "    return ";
1609       } else {
1610         offset_prefix = "  const offset = " + GenBBAccess() +
1611                         ".__offset(this.bb_pos, " +
1612                         NumToString(field.value.offset) + ");\n";
1613         offset_prefix += "  return offset ? ";
1614       }
1615 
1616       // Emit a scalar field
1617       const auto is_string = IsString(field.value.type);
1618       if (IsScalar(field.value.type.base_type) || is_string) {
1619         const auto has_null_default = is_string || HasNullDefault(field);
1620 
1621         GenDocComment(field.doc_comment, code_ptr);
1622         std::string prefix = namer_.Method(field) + "(";
1623         if (is_string) {
1624           code += prefix + "):string|null\n";
1625           code +=
1626               prefix + "optionalEncoding:flatbuffers.Encoding" + "):" +
1627               GenTypeName(imports, struct_def, field.value.type, false, true) +
1628               "\n";
1629           code += prefix + "optionalEncoding?:any";
1630         } else {
1631           code += prefix;
1632         }
1633         if (field.value.type.enum_def) {
1634           code += "):" +
1635                   GenTypeName(imports, struct_def, field.value.type, false,
1636                               field.IsOptional()) +
1637                   " {\n";
1638         } else {
1639           code += "):" +
1640                   GenTypeName(imports, struct_def, field.value.type, false,
1641                               has_null_default) +
1642                   " {\n";
1643         }
1644 
1645         if (struct_def.fixed) {
1646           code +=
1647               "  return " +
1648               GenGetter(field.value.type,
1649                         "(this.bb_pos" + MaybeAdd(field.value.offset) + ")") +
1650               ";\n";
1651         } else {
1652           std::string index = "this.bb_pos + offset";
1653           if (is_string) { index += ", optionalEncoding"; }
1654           code +=
1655               offset_prefix + GenGetter(field.value.type, "(" + index + ")");
1656           if (field.value.type.base_type != BASE_TYPE_ARRAY) {
1657             code += " : " + GenDefaultValue(field, imports);
1658           }
1659           code += ";\n";
1660         }
1661       }
1662 
1663       // Emit an object field
1664       else {
1665         switch (field.value.type.base_type) {
1666           case BASE_TYPE_STRUCT: {
1667             const auto type =
1668                 AddImport(imports, struct_def, *field.value.type.struct_def)
1669                     .name;
1670             GenDocComment(field.doc_comment, code_ptr);
1671             code += namer_.Method(field);
1672             code += "(obj?:" + type + "):" + type + "|null {\n";
1673 
1674             if (struct_def.fixed) {
1675               code += "  return (obj || " + GenerateNewExpression(type);
1676               code += ").__init(this.bb_pos";
1677               code +=
1678                   MaybeAdd(field.value.offset) + ", " + GenBBAccess() + ");\n";
1679             } else {
1680               code += offset_prefix + "(obj || " + GenerateNewExpression(type) +
1681                       ").__init(";
1682               code += field.value.type.struct_def->fixed
1683                           ? "this.bb_pos + offset"
1684                           : GenBBAccess() + ".__indirect(this.bb_pos + offset)";
1685               code += ", " + GenBBAccess() + ") : null;\n";
1686             }
1687 
1688             break;
1689           }
1690 
1691           case BASE_TYPE_ARRAY: {
1692             auto vectortype = field.value.type.VectorType();
1693             auto vectortypename =
1694                 GenTypeName(imports, struct_def, vectortype, false);
1695             auto inline_size = InlineSize(vectortype);
1696             auto index = "this.bb_pos + " + NumToString(field.value.offset) +
1697                          " + index" + MaybeScale(inline_size);
1698             std::string ret_type;
1699             bool is_union = false;
1700             switch (vectortype.base_type) {
1701               case BASE_TYPE_STRUCT: ret_type = vectortypename; break;
1702               case BASE_TYPE_STRING: ret_type = vectortypename; break;
1703               case BASE_TYPE_UNION:
1704                 ret_type = "?flatbuffers.Table";
1705                 is_union = true;
1706                 break;
1707               default: ret_type = vectortypename;
1708             }
1709             GenDocComment(field.doc_comment, code_ptr);
1710             std::string prefix = namer_.Method(field);
1711             // TODO: make it work without any
1712             // if (is_union) { prefix += "<T extends flatbuffers.Table>"; }
1713             if (is_union) { prefix += ""; }
1714             prefix += "(index: number";
1715             if (is_union) {
1716               const auto union_type =
1717                   GenUnionGenericTypeTS(*(field.value.type.enum_def));
1718 
1719               vectortypename = union_type;
1720               code += prefix + ", obj:" + union_type;
1721             } else if (vectortype.base_type == BASE_TYPE_STRUCT) {
1722               code += prefix + ", obj?:" + vectortypename;
1723             } else if (IsString(vectortype)) {
1724               code += prefix + "):string\n";
1725               code += prefix + ",optionalEncoding:flatbuffers.Encoding" +
1726                       "):" + vectortypename + "\n";
1727               code += prefix + ",optionalEncoding?:any";
1728             } else {
1729               code += prefix;
1730             }
1731             code += "):" + vectortypename + "|null {\n";
1732 
1733             if (vectortype.base_type == BASE_TYPE_STRUCT) {
1734               code += offset_prefix + "(obj || " +
1735                       GenerateNewExpression(vectortypename);
1736               code += ").__init(";
1737               code += vectortype.struct_def->fixed
1738                           ? index
1739                           : GenBBAccess() + ".__indirect(" + index + ")";
1740               code += ", " + GenBBAccess() + ")";
1741             } else {
1742               if (is_union) {
1743                 index = "obj, " + index;
1744               } else if (IsString(vectortype)) {
1745                 index += ", optionalEncoding";
1746               }
1747               code += offset_prefix + GenGetter(vectortype, "(" + index + ")");
1748             }
1749 
1750             switch (field.value.type.base_type) {
1751               case BASE_TYPE_ARRAY: {
1752                 break;
1753               }
1754               case BASE_TYPE_BOOL: {
1755                 code += " : false";
1756                 break;
1757               }
1758               case BASE_TYPE_LONG:
1759               case BASE_TYPE_ULONG: {
1760                 code += " : BigInt(0)";
1761                 break;
1762               }
1763               default: {
1764                 if (IsScalar(field.value.type.element)) {
1765                   if (field.value.type.enum_def) {
1766                     code += field.value.constant;
1767                   } else {
1768                     code += " : 0";
1769                   }
1770                 } else {
1771                   code += ": null";
1772                 }
1773                 break;
1774               }
1775             }
1776             code += ";\n";
1777             break;
1778           }
1779 
1780           case BASE_TYPE_VECTOR: {
1781             auto vectortype = field.value.type.VectorType();
1782             auto vectortypename =
1783                 GenTypeName(imports, struct_def, vectortype, false);
1784             auto type = GetUnderlyingVectorType(vectortype);
1785             auto inline_size = InlineSize(type);
1786             auto index = GenBBAccess() +
1787                          ".__vector(this.bb_pos + offset) + index" +
1788                          MaybeScale(inline_size);
1789             std::string ret_type;
1790             bool is_union = false;
1791             switch (vectortype.base_type) {
1792               case BASE_TYPE_STRUCT: ret_type = vectortypename; break;
1793               case BASE_TYPE_STRING: ret_type = vectortypename; break;
1794               case BASE_TYPE_UNION:
1795                 ret_type = "?flatbuffers.Table";
1796                 is_union = true;
1797                 break;
1798               default: ret_type = vectortypename;
1799             }
1800             GenDocComment(field.doc_comment, code_ptr);
1801             std::string prefix = namer_.Method(field);
1802             // TODO: make it work without any
1803             // if (is_union) { prefix += "<T extends flatbuffers.Table>"; }
1804             if (is_union) { prefix += ""; }
1805             prefix += "(index: number";
1806             if (is_union) {
1807               const auto union_type =
1808                   GenUnionGenericTypeTS(*(field.value.type.enum_def));
1809 
1810               vectortypename = union_type;
1811               code += prefix + ", obj:" + union_type;
1812             } else if (vectortype.base_type == BASE_TYPE_STRUCT) {
1813               code += prefix + ", obj?:" + vectortypename;
1814             } else if (IsString(vectortype)) {
1815               code += prefix + "):string\n";
1816               code += prefix + ",optionalEncoding:flatbuffers.Encoding" +
1817                       "):" + vectortypename + "\n";
1818               code += prefix + ",optionalEncoding?:any";
1819             } else {
1820               code += prefix;
1821             }
1822             code += "):" + vectortypename + "|null {\n";
1823 
1824             if (vectortype.base_type == BASE_TYPE_STRUCT) {
1825               code += offset_prefix + "(obj || " +
1826                       GenerateNewExpression(vectortypename);
1827               code += ").__init(";
1828               code += vectortype.struct_def->fixed
1829                           ? index
1830                           : GenBBAccess() + ".__indirect(" + index + ")";
1831               code += ", " + GenBBAccess() + ")";
1832             } else {
1833               if (is_union) {
1834                 index = "obj, " + index;
1835               } else if (IsString(vectortype)) {
1836                 index += ", optionalEncoding";
1837               }
1838               code += offset_prefix + GenGetter(vectortype, "(" + index + ")");
1839             }
1840             code += " : ";
1841             if (field.value.type.element == BASE_TYPE_BOOL) {
1842               code += "false";
1843             } else if (field.value.type.element == BASE_TYPE_LONG ||
1844                        field.value.type.element == BASE_TYPE_ULONG) {
1845               code += "BigInt(0)";
1846             } else if (IsScalar(field.value.type.element)) {
1847               if (field.value.type.enum_def) {
1848                 code += field.value.constant;
1849               } else {
1850                 code += "0";
1851               }
1852             } else {
1853               code += "null";
1854             }
1855             code += ";\n";
1856             break;
1857           }
1858 
1859           case BASE_TYPE_UNION: {
1860             GenDocComment(field.doc_comment, code_ptr);
1861             code += namer_.Method(field);
1862 
1863             const auto &union_enum = *(field.value.type.enum_def);
1864             const auto union_type = GenUnionGenericTypeTS(union_enum);
1865             code += "<T extends flatbuffers.Table>(obj:" + union_type +
1866                     "):" + union_type +
1867                     "|null "
1868                     "{\n";
1869 
1870             code += offset_prefix +
1871                     GenGetter(field.value.type, "(obj, this.bb_pos + offset)") +
1872                     " : null;\n";
1873             break;
1874           }
1875           default: FLATBUFFERS_ASSERT(0);
1876         }
1877       }
1878       code += "}\n\n";
1879 
1880       // Adds the mutable scalar value to the output
1881       if (IsScalar(field.value.type.base_type) && parser.opts.mutable_buffer &&
1882           !IsUnion(field.value.type)) {
1883         std::string type =
1884             GenTypeName(imports, struct_def, field.value.type, true);
1885 
1886         code += namer_.LegacyTsMutateMethod(field) + "(value:" + type +
1887                 "):boolean {\n";
1888 
1889         const std::string write_method =
1890             "." + namer_.Method("write", GenType(field.value.type));
1891 
1892         if (struct_def.fixed) {
1893           code += "  " + GenBBAccess() + write_method + "(this.bb_pos + " +
1894                   NumToString(field.value.offset) + ", ";
1895         } else {
1896           code += "  const offset = " + GenBBAccess() +
1897                   ".__offset(this.bb_pos, " + NumToString(field.value.offset) +
1898                   ");\n\n";
1899           code += "  if (offset === 0) {\n";
1900           code += "    return false;\n";
1901           code += "  }\n\n";
1902 
1903           // special case for bools, which are treated as uint8
1904           code +=
1905               "  " + GenBBAccess() + write_method + "(this.bb_pos + offset, ";
1906           if (field.value.type.base_type == BASE_TYPE_BOOL) { code += "+"; }
1907         }
1908 
1909         code += "value);\n";
1910         code += "  return true;\n";
1911         code += "}\n\n";
1912       }
1913 
1914       // Emit vector helpers
1915       if (IsVector(field.value.type)) {
1916         // Emit a length helper
1917         GenDocComment(code_ptr);
1918         code += namer_.Method(field, "Length");
1919         code += "():number {\n" + offset_prefix;
1920 
1921         code +=
1922             GenBBAccess() + ".__vector_len(this.bb_pos + offset) : 0;\n}\n\n";
1923 
1924         // For scalar types, emit a typed array helper
1925         auto vectorType = field.value.type.VectorType();
1926         if (IsScalar(vectorType.base_type) && !IsLong(vectorType.base_type)) {
1927           GenDocComment(code_ptr);
1928 
1929           code += namer_.Method(field, "Array");
1930           code +=
1931               "():" + GenType(vectorType) + "Array|null {\n" + offset_prefix;
1932 
1933           code += "new " + GenType(vectorType) + "Array(" + GenBBAccess() +
1934                   ".bytes().buffer, " + GenBBAccess() +
1935                   ".bytes().byteOffset + " + GenBBAccess() +
1936                   ".__vector(this.bb_pos + offset), " + GenBBAccess() +
1937                   ".__vector_len(this.bb_pos + offset)) : null;\n}\n\n";
1938         }
1939       }
1940     }
1941 
1942     // Emit the fully qualified name
1943     if (parser_.opts.generate_name_strings) {
1944       GenDocComment(code_ptr);
1945       code += "static getFullyQualifiedName():string {\n";
1946       code +=
1947           "  return '" +
1948           struct_def.defined_namespace->GetFullyQualifiedName(struct_def.name) +
1949           "';\n";
1950       code += "}\n\n";
1951     }
1952 
1953     // Emit the size of the struct.
1954     if (struct_def.fixed) {
1955       GenDocComment(code_ptr);
1956       code += "static sizeOf():number {\n";
1957       code += "  return " + NumToString(struct_def.bytesize) + ";\n";
1958       code += "}\n\n";
1959     }
1960 
1961     // Emit a factory constructor
1962     if (struct_def.fixed) {
1963       std::string arguments;
1964       GenStructArgs(imports, struct_def, &arguments, "");
1965       GenDocComment(code_ptr);
1966 
1967       code += "static create" + GetPrefixedName(struct_def) +
1968               "(builder:flatbuffers.Builder";
1969       code += arguments + "):flatbuffers.Offset {\n";
1970 
1971       GenStructBody(struct_def, &code, "");
1972       code += "  return builder.offset();\n}\n\n";
1973     } else {
1974       // Generate a method to start building a new object
1975       GenDocComment(code_ptr);
1976 
1977       code += "static start" + GetPrefixedName(struct_def) +
1978               "(builder:flatbuffers.Builder) {\n";
1979 
1980       code += "  builder.startObject(" +
1981               NumToString(struct_def.fields.vec.size()) + ");\n";
1982       code += "}\n\n";
1983 
1984       // Generate a set of static methods that allow table construction
1985       for (auto it = struct_def.fields.vec.begin();
1986            it != struct_def.fields.vec.end(); ++it) {
1987         auto &field = **it;
1988         if (field.deprecated) continue;
1989         const auto argname = GetArgName(field);
1990 
1991         // Generate the field insertion method
1992         GenDocComment(code_ptr);
1993         code += "static " + namer_.Method("add", field);
1994         code += "(builder:flatbuffers.Builder, " + argname + ":" +
1995                 GetArgType(imports, struct_def, field, false) + ") {\n";
1996         code += "  builder.addField" + GenWriteMethod(field.value.type) + "(";
1997         code += NumToString(it - struct_def.fields.vec.begin()) + ", ";
1998         if (field.value.type.base_type == BASE_TYPE_BOOL) { code += "+"; }
1999         code += argname + ", ";
2000         if (!IsScalar(field.value.type.base_type)) {
2001           code += "0";
2002         } else if (HasNullDefault(field)) {
2003           code += "null";
2004         } else {
2005           if (field.value.type.base_type == BASE_TYPE_BOOL) { code += "+"; }
2006           code += GenDefaultValue(field, imports);
2007         }
2008         code += ");\n}\n\n";
2009 
2010         if (IsVector(field.value.type)) {
2011           auto vector_type = field.value.type.VectorType();
2012           auto type = GetUnderlyingVectorType(vector_type);
2013           auto alignment = InlineAlignment(type);
2014           auto elem_size = InlineSize(type);
2015 
2016           // Generate a method to create a vector from a JavaScript array
2017           if (!IsStruct(vector_type)) {
2018             GenDocComment(code_ptr);
2019 
2020             const std::string sig_begin =
2021                 "static " + namer_.Method("create", field, "Vector") +
2022                 "(builder:flatbuffers.Builder, data:";
2023             const std::string sig_end = "):flatbuffers.Offset";
2024             std::string type =
2025                 GenTypeName(imports, struct_def, vector_type, true) + "[]";
2026             if (type == "number[]") {
2027               const auto &array_type = GenType(vector_type);
2028               // the old type should be deprecated in the future
2029               std::string type_old = "number[]|Uint8Array";
2030               std::string type_new = "number[]|" + array_type + "Array";
2031               if (type_old == type_new) {
2032                 type = type_new;
2033               } else {
2034                 // add function overloads
2035                 code += sig_begin + type_new + sig_end + ";\n";
2036                 code +=
2037                     "/**\n * @deprecated This Uint8Array overload will "
2038                     "be removed in the future.\n */\n";
2039                 code += sig_begin + type_old + sig_end + ";\n";
2040                 type = type_new + "|Uint8Array";
2041               }
2042             }
2043             code += sig_begin + type + sig_end + " {\n";
2044             code += "  builder.startVector(" + NumToString(elem_size);
2045             code += ", data.length, " + NumToString(alignment) + ");\n";
2046             code += "  for (let i = data.length - 1; i >= 0; i--) {\n";
2047             code += "    builder.add" + GenWriteMethod(vector_type) + "(";
2048             if (vector_type.base_type == BASE_TYPE_BOOL) { code += "+"; }
2049             code += "data[i]!);\n";
2050             code += "  }\n";
2051             code += "  return builder.endVector();\n";
2052             code += "}\n\n";
2053           }
2054 
2055           // Generate a method to start a vector, data to be added manually
2056           // after
2057           GenDocComment(code_ptr);
2058 
2059           code += "static ";
2060           code += namer_.Method("start", field, "Vector");
2061           code += "(builder:flatbuffers.Builder, numElems:number) {\n";
2062           code += "  builder.startVector(" + NumToString(elem_size);
2063           code += ", numElems, " + NumToString(alignment) + ");\n";
2064           code += "}\n\n";
2065         }
2066       }
2067 
2068       // Generate a method to stop building a new object
2069       GenDocComment(code_ptr);
2070 
2071       code += "static end" + GetPrefixedName(struct_def);
2072       code += "(builder:flatbuffers.Builder):flatbuffers.Offset {\n";
2073 
2074       code += "  const offset = builder.endObject();\n";
2075       for (auto it = struct_def.fields.vec.begin();
2076            it != struct_def.fields.vec.end(); ++it) {
2077         auto &field = **it;
2078         if (!field.deprecated && field.IsRequired()) {
2079           code += "  builder.requiredField(offset, ";
2080           code += NumToString(field.value.offset);
2081           code += ") // " + field.name + "\n";
2082         }
2083       }
2084       code += "  return offset;\n";
2085       code += "}\n\n";
2086 
2087       // Generate the methods to complete buffer construction
2088       GenerateFinisher(struct_def, code_ptr, code, false);
2089       GenerateFinisher(struct_def, code_ptr, code, true);
2090 
2091       // Generate a convenient CreateX function
2092       if (CanCreateFactoryMethod(struct_def)) {
2093         code += "static create" + GetPrefixedName(struct_def);
2094         code += "(builder:flatbuffers.Builder";
2095         for (auto it = struct_def.fields.vec.begin();
2096              it != struct_def.fields.vec.end(); ++it) {
2097           const auto &field = **it;
2098           if (field.deprecated) continue;
2099           code += ", " + GetArgName(field) + ":" +
2100                   GetArgType(imports, struct_def, field, true);
2101         }
2102 
2103         code += "):flatbuffers.Offset {\n";
2104         code += "  " + object_name + ".start" + GetPrefixedName(struct_def) +
2105                 "(builder);\n";
2106 
2107         std::string methodPrefix = object_name;
2108         for (auto it = struct_def.fields.vec.begin();
2109              it != struct_def.fields.vec.end(); ++it) {
2110           const auto &field = **it;
2111           if (field.deprecated) continue;
2112 
2113           const auto arg_name = GetArgName(field);
2114 
2115           if (field.IsScalarOptional()) {
2116             code += "  if (" + arg_name + " !== null)\n  ";
2117           }
2118 
2119           code += "  " + methodPrefix + "." + namer_.Method("add", field) + "(";
2120           code += "builder, " + arg_name + ");\n";
2121         }
2122 
2123         code += "  return " + methodPrefix + ".end" +
2124                 GetPrefixedName(struct_def) + "(builder);\n";
2125         code += "}\n";
2126       }
2127     }
2128 
2129     if (!struct_def.fixed && parser_.services_.vec.size() != 0) {
2130       auto name = GetPrefixedName(struct_def, "");
2131       code += "\n";
2132       code += "serialize():Uint8Array {\n";
2133       code += "  return this.bb!.bytes();\n";
2134       code += "}\n";
2135 
2136       code += "\n";
2137       code += "static deserialize(buffer: Uint8Array):" +
2138               namer_.EscapeKeyword(name) + " {\n";
2139       code += "  return " + AddImport(imports, struct_def, struct_def).name +
2140               ".getRootAs" + name + "(new flatbuffers.ByteBuffer(buffer))\n";
2141       code += "}\n";
2142     }
2143 
2144     if (parser_.opts.generate_object_based_api) {
2145       std::string obj_api_class;
2146       std::string obj_api_unpack_func;
2147       GenObjApi(parser_, struct_def, obj_api_unpack_func, obj_api_class,
2148                 imports);
2149 
2150       code += obj_api_unpack_func + "}\n" + obj_api_class;
2151     } else {
2152       code += "}\n";
2153     }
2154   }
2155 
HasNullDefault(const FieldDef & field)2156   static bool HasNullDefault(const FieldDef &field) {
2157     return field.IsOptional() && field.value.constant == "null";
2158   }
2159 
GetArgType(import_set & imports,const Definition & owner,const FieldDef & field,bool allowNull)2160   std::string GetArgType(import_set &imports, const Definition &owner,
2161                          const FieldDef &field, bool allowNull) {
2162     return GenTypeName(imports, owner, field.value.type, true,
2163                        allowNull && field.IsOptional());
2164   }
2165 
GetArgName(const FieldDef & field)2166   std::string GetArgName(const FieldDef &field) {
2167     auto argname = namer_.Variable(field);
2168     if (!IsScalar(field.value.type.base_type)) { argname += "Offset"; }
2169     return argname;
2170   }
2171 
GetPrefixedName(const StructDef & struct_def,const char * prefix="")2172   std::string GetPrefixedName(const StructDef &struct_def,
2173                               const char *prefix = "") {
2174     return prefix + struct_def.name;
2175   }
2176 };  // namespace ts
2177 }  // namespace ts
2178 
GenerateTS(const Parser & parser,const std::string & path,const std::string & file_name)2179 static bool GenerateTS(const Parser &parser, const std::string &path,
2180                        const std::string &file_name) {
2181   ts::TsGenerator generator(parser, path, file_name);
2182   return generator.generate();
2183 }
2184 
TSMakeRule(const Parser & parser,const std::string & path,const std::string & file_name)2185 static std::string TSMakeRule(const Parser &parser, const std::string &path,
2186                               const std::string &file_name) {
2187   std::string filebase =
2188       flatbuffers::StripPath(flatbuffers::StripExtension(file_name));
2189   ts::TsGenerator generator(parser, path, file_name);
2190   std::string make_rule =
2191       generator.GeneratedFileName(path, filebase, parser.opts) + ": ";
2192 
2193   auto included_files = parser.GetIncludedFilesRecursive(file_name);
2194   for (auto it = included_files.begin(); it != included_files.end(); ++it) {
2195     make_rule += " " + *it;
2196   }
2197   return make_rule;
2198 }
2199 
2200 namespace {
2201 
2202 class TsCodeGenerator : public CodeGenerator {
2203  public:
GenerateCode(const Parser & parser,const std::string & path,const std::string & filename)2204   Status GenerateCode(const Parser &parser, const std::string &path,
2205                       const std::string &filename) override {
2206     if (!GenerateTS(parser, path, filename)) { return Status::ERROR; }
2207     return Status::OK;
2208   }
2209 
GenerateCode(const uint8_t *,int64_t,const CodeGenOptions &)2210   Status GenerateCode(const uint8_t *, int64_t,
2211                       const CodeGenOptions &) override {
2212     return Status::NOT_IMPLEMENTED;
2213   }
2214 
GenerateMakeRule(const Parser & parser,const std::string & path,const std::string & filename,std::string & output)2215   Status GenerateMakeRule(const Parser &parser, const std::string &path,
2216                           const std::string &filename,
2217                           std::string &output) override {
2218     output = TSMakeRule(parser, path, filename);
2219     return Status::OK;
2220   }
2221 
GenerateGrpcCode(const Parser & parser,const std::string & path,const std::string & filename)2222   Status GenerateGrpcCode(const Parser &parser, const std::string &path,
2223                           const std::string &filename) override {
2224     if (!GenerateTSGRPC(parser, path, filename)) { return Status::ERROR; }
2225     return Status::OK;
2226   }
2227 
GenerateRootFile(const Parser & parser,const std::string & path)2228   Status GenerateRootFile(const Parser &parser,
2229                           const std::string &path) override {
2230     (void)parser;
2231     (void)path;
2232     return Status::NOT_IMPLEMENTED;
2233   }
IsSchemaOnly() const2234   bool IsSchemaOnly() const override { return true; }
2235 
SupportsBfbsGeneration() const2236   bool SupportsBfbsGeneration() const override { return false; }
SupportsRootFileGeneration() const2237   bool SupportsRootFileGeneration() const override { return false; }
2238 
Language() const2239   IDLOptions::Language Language() const override { return IDLOptions::kTs; }
2240 
LanguageName() const2241   std::string LanguageName() const override { return "TS"; }
2242 };
2243 }  // namespace
2244 
NewTsCodeGenerator()2245 std::unique_ptr<CodeGenerator> NewTsCodeGenerator() {
2246   return std::unique_ptr<TsCodeGenerator>(new TsCodeGenerator());
2247 }
2248 
2249 }  // namespace flatbuffers
2250