refactor(@angular-devkit/schematics): replace usage of deprecated JSON parser with jsonc-parser

Author: alan-agius4

goldens/public-api/angular_devkit/schematics/tools/index.md

@@ -8,14 +8,12 @@
 
 import { analytics } from '@angular-devkit/core';
 import { BaseException } from '@angular-devkit/core';
-import { InvalidJsonCharacterException } from '@angular-devkit/core';
 import { JsonObject } from '@angular-devkit/core';
 import { logging } from '@angular-devkit/core';
 import { Observable } from 'rxjs';
 import { Path } from '@angular-devkit/core';
 import { PathFragment } from '@angular-devkit/core';
 import { schema } from '@angular-devkit/core';
-import { UnexpectedEndOfInputException } from '@angular-devkit/core';
 import { Url } from 'url';
 import { virtualFs } from '@angular-devkit/core';
 import { workflow } from '@angular-devkit/schematics';
@@ -177,7 +175,7 @@ export interface FileSystemSchematicJsonDescription {
 
 // @public (undocumented)
 export class InvalidCollectionJsonException extends BaseException {
-    constructor(_name: string, path: string, jsonException?: UnexpectedEndOfInputException | InvalidJsonCharacterException);
+    constructor(_name: string, path: string, jsonException?: Error);
 }
 
 // @public

packages/angular_devkit/schematics/package.json

@@ -14,6 +14,7 @@
   ],
   "dependencies": {
     "@angular-devkit/core": "0.0.0",
+    "jsonc-parser": "3.0.0",
     "ora": "5.4.1",
     "rxjs": "6.6.7"
   }

packages/angular_devkit/schematics/tools/BUILD.bazel

@@ -31,6 +31,7 @@ ts_library(
         "//packages/angular_devkit/schematics/tasks",
         "//packages/angular_devkit/schematics/tasks/node",
         "@npm//@types/node",
+        "@npm//jsonc-parser",
         "@npm//rxjs",
     ],
 )

packages/angular_devkit/schematics/tools/file-system-engine-host-base.ts

@@ -6,14 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {
-  BaseException,
-  InvalidJsonCharacterException,
-  JsonObject,
-  UnexpectedEndOfInputException,
-  normalize,
-  virtualFs,
-} from '@angular-devkit/core';
+import { BaseException, JsonObject, normalize, virtualFs } from '@angular-devkit/core';
 import { NodeJsSyncHost } from '@angular-devkit/core/node';
 import { existsSync, statSync } from 'fs';
 import { dirname, isAbsolute, join, resolve } from 'path';
@@ -51,11 +44,7 @@ export class CollectionCannotBeResolvedException extends BaseException {
   }
 }
 export class InvalidCollectionJsonException extends BaseException {
-  constructor(
-    _name: string,
-    path: string,
-    jsonException?: UnexpectedEndOfInputException | InvalidJsonCharacterException,
-  ) {
+  constructor(_name: string, path: string, jsonException?: Error) {
     let msg = `Collection JSON at path ${JSON.stringify(path)} is invalid.`;
 
     if (jsonException) {
@@ -320,7 +309,7 @@ export abstract class FileSystemEngineHostBase implements FileSystemEngineHost {
       return transformedOptions;
     };
 
-    return (observableFrom(transform()) as unknown) as Observable<ResultT>;
+    return observableFrom(transform()) as unknown as Observable<ResultT>;
   }
 
   transformContext(context: FileSystemSchematicContext): FileSystemSchematicContext {

packages/angular_devkit/schematics/tools/file-system-utility.ts

@@ -6,48 +6,27 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {
-  FileDoesNotExistException,
-  JsonParseMode,
-  JsonValue,
-  parseJson,
-} from '@angular-devkit/core';
+import { JsonValue } from '@angular-devkit/core';
+import { FileDoesNotExistException } from '@angular-devkit/schematics';
 import { existsSync, readFileSync } from 'fs';
+import { ParseError, parse, printParseErrorCode } from 'jsonc-parser';
 
-/**
- * Read a file and returns its content. This supports different file encoding.
- */
-export function readFile(fileName: string): string {
-  if (!existsSync(fileName)) {
-    throw new FileDoesNotExistException(fileName);
+export function readJsonFile(path: string): JsonValue {
+  if (!existsSync(path)) {
+    throw new FileDoesNotExistException(path);
   }
-  const buffer = readFileSync(fileName);
-  let len = buffer.length;
-  if (len >= 2 && buffer[0] === 0xfe && buffer[1] === 0xff) {
-    // Big endian UTF-16 byte order mark detected. Since big endian is not supported by node.js,
-    // flip all byte pairs and treat as little endian.
-    len &= ~1;
-    for (let i = 0; i < len; i += 2) {
-      const temp = buffer[i];
-      buffer[i] = buffer[i + 1];
-      buffer[i + 1] = temp;
-    }
 
-    return buffer.toString('utf16le', 2);
-  }
-  if (len >= 2 && buffer[0] === 0xff && buffer[1] === 0xfe) {
-    // Little endian UTF-16 byte order mark detected
-    return buffer.toString('utf16le', 2);
-  }
-  if (len >= 3 && buffer[0] === 0xef && buffer[1] === 0xbb && buffer[2] === 0xbf) {
-    // UTF-8 byte order mark detected
-    return buffer.toString('utf8', 3);
-  }
+  const errors: ParseError[] = [];
+  const content = parse(readFileSync(path, 'utf-8'), errors, { allowTrailingComma: true });
 
-  // Default is UTF-8 with no byte order mark
-  return buffer.toString('utf8');
-}
+  if (errors.length) {
+    const { error, offset } = errors[0];
+    throw new Error(
+      `Failed to parse "${path}" as JSON AST Object. ${printParseErrorCode(
+        error,
+      )} at location: ${offset}.`,
+    );
+  }
 
-export function readJsonFile(path: string): JsonValue {
-  return parseJson(readFile(path), JsonParseMode.Loose);
+  return content;
 }

packages/angular_devkit/schematics/tools/node-module-engine-host.ts

@@ -6,11 +6,7 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {
-  BaseException,
-  InvalidJsonCharacterException,
-  UnexpectedEndOfInputException,
-} from '@angular-devkit/core';
+import { BaseException } from '@angular-devkit/core';
 import { dirname, join, resolve } from 'path';
 import { RuleFactory } from '../src';
 import { FileSystemCollectionDesc, FileSystemSchematicDesc } from './description';
@@ -19,7 +15,6 @@ import {
   CollectionCannotBeResolvedException,
   CollectionMissingSchematicsMapException,
   FileSystemEngineHostBase,
-  InvalidCollectionJsonException,
   SchematicMissingFieldsException,
 } from './file-system-engine-host-base';
 import { readJsonFile } from './file-system-utility';
@@ -98,21 +93,9 @@ export class NodeModulesEngineHost extends FileSystemEngineHostBase {
 
   protected _resolveCollectionPath(name: string, requester?: string): string {
     const collectionPath = this.resolve(name, requester);
+    readJsonFile(collectionPath);
 
-    try {
-      readJsonFile(collectionPath);
-
-      return collectionPath;
-    } catch (e) {
-      if (
-        e instanceof InvalidJsonCharacterException ||
-        e instanceof UnexpectedEndOfInputException
-      ) {
-        throw new InvalidCollectionJsonException(name, collectionPath, e);
-      } else {
-        throw e;
-      }
-    }
+    return collectionPath;
   }
 
   protected _resolveReferenceString(refString: string, parentPath: string) {