1/* 2 * Copyright (c) 2022-2024 Huawei Device Co., Ltd. 3 * Licensed under the Apache License, Version 2.0 (the "License"); 4 * you may not use this file except in compliance with the License. 5 * You may obtain a copy of the License at 6 * 7 * http://www.apache.org/licenses/LICENSE-2.0 8 * 9 * Unless required by applicable law or agreed to in writing, software 10 * distributed under the License is distributed on an "AS IS" BASIS, 11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 * See the License for the specific language governing permissions and 13 * limitations under the License. 14 */ 15 16import type * as ts from 'typescript'; 17 18/** 19 * NOTE: hack for typecheck of readonly arrays. 20 * See more here https://github.com/microsoft/TypeScript/issues/17002 21 */ 22declare global { 23 interface ArrayConstructor { 24 isArray(arg: unknown): arg is unknown[] | readonly unknown[]; 25 } 26} 27 28export function isVisitResultNode(vr: ts.VisitResult<ts.Node>): vr is ts.Node { 29 return vr !== undefined && !Array.isArray(vr); 30} 31 32export function isVisitResultNodeArray(vr: ts.VisitResult<ts.Node>): vr is readonly ts.Node[] { 33 return Array.isArray(vr); 34} 35 36export function visitVisitResult(result: ts.VisitResult<ts.Node>, visitor: ts.Visitor): ts.VisitResult<ts.Node> { 37 if (result === undefined) { 38 return undefined; 39 } 40 41 if (isVisitResultNode(result)) { 42 return visitor(result); 43 } 44 45 if (!isVisitResultNodeArray(result)) { 46 throw new Error('Unreachable'); 47 } 48 49 const newResult: ts.Node[] = []; 50 for (const node of result) { 51 const fixedNode = visitor(node); 52 53 if (fixedNode === undefined) { 54 continue; 55 } 56 57 if (Array.isArray(fixedNode)) { 58 newResult.push(...fixedNode); 59 continue; 60 } 61 62 newResult.push(fixedNode); 63 } 64 65 if (newResult.length === 0) { 66 return undefined; 67 } 68 69 if (newResult.length === 1) { 70 return newResult[0]; 71 } 72 73 return newResult; 74} 75