Function runFormatterInParallel

ng-dev/format/run-commands-parallel.ts:44–137

(allFiles: string[], action: FormatterAction)

 * The promise resolves with a list of failures, or `false` if no formatters have matched.
 */
export function runFormatterInParallel(allFiles: string[], action: FormatterAction) {
  return new Promise<false | FormatFailure[]>(async (resolve) => {
    const formatters = await getActiveFormatters();
    const failures: FormatFailure[] = [];
    const pendingCommands: {formatter: Formatter; file: string}[] = [];

    for (const formatter of formatters) {
      pendingCommands.push(
        ...multimatch
          .call(undefined, allFiles, formatter.getFileMatcher(), {dot: true})
          .map((file) => ({formatter, file})),
      );
    }

    // If no commands are generated, resolve the promise as `false` as no files
    // were run against the any formatters.
    if (pendingCommands.length === 0) {
      return resolve(false);
    }

    switch (action) {
      case 'format':
        Log.info(`Formatting ${pendingCommands.length} file(s)`);
        break;
      case 'check':
        Log.info(`Checking format of ${pendingCommands.length} file(s)`);
        break;
      default:
        throw Error(`Invalid format action "${action}": allowed actions are "format" and "check"`);
    }

    // The progress bar instance to use for progress tracking.
    const progressBar = new Bar({
      format: `[{bar}] ETA: {eta}s | {value}/{total} files`,
      clearOnComplete: true,
    });
    // A local copy of the files to run the command on.
    // An array to represent the current usage state of each of the threads for parallelization.
    const threads = new Array<boolean>(AVAILABLE_THREADS).fill(false);

    // Recursively run the command on the next available file from the list using the provided
    // thread.
    function runCommandInThread(thread: number) {
      const nextCommand = pendingCommands.pop();
      // If no file was pulled from the array, return as there are no more files to run against.
      if (nextCommand === undefined) {
        threads[thread] = false;
        return;
      }

      // Get the file and formatter for the next command.
      const {file, formatter} = nextCommand;

      if (lstatSync(file).isSymbolicLink()) {
        throw new Error(`Security violation: symlink detected for file ${file}`);
      }

      const [spawnCmd, ...spawnArgs] = [...formatter.commandFor(action), '--', file];