Class NodeJsAsyncHost

packages/angular_devkit/core/node/host.ts:64–152

 * synchronous and one asynchronous.
 */
export class NodeJsAsyncHost implements virtualFs.Host<Stats> {
  get capabilities(): virtualFs.HostCapabilities {
    return { synchronous: false };
  }

  write(path: Path, content: virtualFs.FileBuffer): Observable<void> {
    return observableFrom(fsPromises.mkdir(getSystemPath(dirname(path)), { recursive: true })).pipe(
      mergeMap(() => fsPromises.writeFile(getSystemPath(path), new Uint8Array(content))),
    );
  }

  read(path: Path): Observable<virtualFs.FileBuffer> {
    return observableFrom(fsPromises.readFile(getSystemPath(path))).pipe(
      map((buffer) => new Uint8Array(buffer).buffer),
    );
  }

  delete(path: Path): Observable<void> {
    return observableFrom(
      fsPromises.rm(getSystemPath(path), { force: true, recursive: true, maxRetries: 3 }),
    );
  }

  rename(from: Path, to: Path): Observable<void> {
    return observableFrom(fsPromises.rename(getSystemPath(from), getSystemPath(to)));
  }

  list(path: Path): Observable<PathFragment[]> {
    return observableFrom(fsPromises.readdir(getSystemPath(path))).pipe(
      map((names) => names.map((name) => fragment(name))),
    );
  }

  exists(path: Path): Observable<boolean> {
    return observableFrom(exists(getSystemPath(path)));
  }

  isDirectory(path: Path): Observable<boolean> {
    return this.stat(path).pipe(map((stat) => stat.isDirectory()));
  }

  isFile(path: Path): Observable<boolean> {
    return this.stat(path).pipe(map((stat) => stat.isFile()));
  }

  // Some hosts may not support stat.
  stat(path: Path): Observable<virtualFs.Stats<Stats>> {
    return observableFrom(fsPromises.stat(getSystemPath(path)));
  }

  // Some hosts may not support watching.
  watch(
    path: Path,
    _options?: virtualFs.HostWatchOptions,
  ): Observable<virtualFs.HostWatchEvent> | null {
    return new Observable<virtualFs.HostWatchEvent>((obs) => {
      loadFSWatcher();
      const watcher = new FSWatcher({ persistent: true });