1/* 2 * Copyright (C) 2023 The Android Open Source Project 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 17import {assertDefined, assertTrue} from './assert_utils'; 18 19/** 20 * Represents a key in an object, which may be a simple key or an array key. 21 */ 22class Key { 23 /** 24 * @param key The key name. 25 * @param index The index of the key in an array, or undefined if it's not an array key. 26 */ 27 constructor(public key: string, public index?: number) {} 28 29 /** 30 * Returns true if the key is an array key. 31 */ 32 isArrayKey(): boolean { 33 return this.index !== undefined; 34 } 35} 36 37/** 38 * Utility class for working with objects. 39 */ 40export class ObjectUtils { 41 private static readonly ARRAY_KEY_REGEX = new RegExp('(.+)\\[(\\d+)\\]'); 42 43 /** 44 * Gets the property at the given path in the object. 45 * 46 * @param obj The object to get the property from. 47 * @param path The path to the property, using dot notation for nested objects. 48 * @return The value of the property at the given path. 49 */ 50 static getProperty(obj: object, path: string): any { 51 const keys = ObjectUtils.parseKeys(path); 52 keys.forEach((key) => { 53 if (obj === undefined) { 54 return; 55 } 56 57 if (key.isArrayKey()) { 58 if ((obj as any)[key.key] === undefined) { 59 return; 60 } 61 assertTrue( 62 Array.isArray((obj as any)[key.key]), 63 () => 'Expected to be array', 64 ); 65 obj = (obj as any)[key.key][assertDefined(key.index)]; 66 } else { 67 obj = (obj as any)[key.key]; 68 } 69 }); 70 return obj; 71 } 72 73 /** 74 * Sets the property at the given path in the object. 75 * 76 * @param obj The object to set the property on. 77 * @param path The path to the property, using dot notation for nested objects. 78 * @param value The value to set the property to. 79 */ 80 static setProperty(obj: object, path: string, value: any) { 81 const keys = ObjectUtils.parseKeys(path); 82 83 keys.slice(0, -1).forEach((key) => { 84 if (key.isArrayKey()) { 85 ObjectUtils.initializePropertyArrayIfNeeded(obj, key); 86 obj = (obj as any)[key.key][assertDefined(key.index)]; 87 } else { 88 ObjectUtils.initializePropertyIfNeeded(obj, key.key); 89 obj = (obj as any)[key.key]; 90 } 91 }); 92 93 const lastKey = assertDefined(keys.at(-1)); 94 if (lastKey.isArrayKey()) { 95 ObjectUtils.initializePropertyArrayIfNeeded(obj, lastKey); 96 (obj as any)[lastKey.key][assertDefined(lastKey.index)] = value; 97 } else { 98 (obj as any)[lastKey.key] = value; 99 } 100 } 101 102 private static parseKeys(path: string): Key[] { 103 return path.split('.').map((rawKey) => { 104 const match = ObjectUtils.ARRAY_KEY_REGEX.exec(rawKey); 105 if (match) { 106 return new Key(match[1], Number(match[2])); 107 } 108 return new Key(rawKey); 109 }); 110 } 111 112 private static initializePropertyIfNeeded(obj: object, key: string) { 113 if ((obj as any)[key] === undefined) { 114 (obj as any)[key] = {}; 115 } 116 assertTrue( 117 typeof (obj as any)[key] === 'object', 118 () => 'Expected to be object', 119 ); 120 } 121 122 private static initializePropertyArrayIfNeeded(obj: object, key: Key) { 123 if ((obj as any)[key.key] === undefined) { 124 (obj as any)[key.key] = []; 125 } 126 if ((obj as any)[key.key][assertDefined(key.index)] === undefined) { 127 (obj as any)[key.key][assertDefined(key.index)] = {}; 128 } 129 assertTrue( 130 Array.isArray((obj as any)[key.key]), 131 () => 'Expected to be array', 132 ); 133 } 134} 135