Function watchedFileChanged

packages/compiler-cli/src/perform_watch.ts:279–311

(event: FileChangeEvent, fileName: string)

  }

  function watchedFileChanged(event: FileChangeEvent, fileName: string) {
    const normalizedPath = path.normalize(fileName);

    if (
      cachedOptions &&
      event === FileChangeEvent.Change &&
      // TODO(chuckj): validate that this is sufficient to skip files that were written.
      // This assumes that the file path we write is the same file path we will receive in the
      // change notification.
      normalizedPath === path.normalize(cachedOptions.project)
    ) {
      // If the configuration file changes, forget everything and start the recompilation timer
      resetOptions();
    } else if (
      event === FileChangeEvent.CreateDelete ||
      event === FileChangeEvent.CreateDeleteDir
    ) {
      // If a file was added or removed, reread the configuration
      // to determine the new list of root files.
      cachedOptions = undefined;
    }

    if (event === FileChangeEvent.CreateDeleteDir) {
      fileCache.clear();
    } else {
      fileCache.delete(normalizedPath);
    }

    if (!ignoreFilesForWatch.has(normalizedPath)) {
      // Ignore the file if the file is one that was written by the compiler.
      startTimerForRecompilation(normalizedPath);
    }
  }

  // Upon detecting a file change, wait for 250ms and then perform a recompilation. This gives batch
  // operations (such as saving all modified files in an editor) a chance to complete before we kick