Class JSONFile

packages/schematics/angular/utility/json-file.ts:27–115

/** @private */
export class JSONFile {
  content: string;
  private eol: string;

  constructor(
    private readonly host: Tree,
    private readonly path: string,
  ) {
    this.content = this.host.readText(this.path);
    this.eol = getEOL(this.content);
  }

  private _jsonAst: Node | undefined;
  private get JsonAst(): Node | undefined {
    if (this._jsonAst) {
      return this._jsonAst;
    }

    const errors: ParseError[] = [];
    this._jsonAst = parseTree(this.content, errors, { allowTrailingComma: true });
    if (errors.length) {
      const { error, offset } = errors[0];
      throw new Error(
        `Failed to parse "${this.path}" as JSON AST Object. ${printParseErrorCode(
          error,
        )} at location: ${offset}.`,
      );
    }

    return this._jsonAst;
  }

  get(jsonPath: JSONPath): unknown {
    const jsonAstNode = this.JsonAst;
    if (!jsonAstNode) {
      return undefined;
    }

    if (jsonPath.length === 0) {
      return getNodeValue(jsonAstNode);
    }

    const node = findNodeAtLocation(jsonAstNode, jsonPath);

    return node === undefined ? undefined : getNodeValue(node);
  }

  modify(
    jsonPath: JSONPath,
    value: JsonValue | undefined,
    insertInOrder?: InsertionIndex | false,
  ): void {
    let getInsertionIndex: InsertionIndex | undefined;
    if (insertInOrder === undefined) {
      const property = jsonPath.slice(-1)[0];
      getInsertionIndex = (properties) =>
        [...properties, property].sort().findIndex((p) => p === property);
    } else if (insertInOrder !== false) {