Method buffer

src/node/utils/Stream.ts:106–122

* Pre-fetch a certain number of values from the underlying iterable before yielding the first * value. Each time a value is yielded (consumed from the buffer), another value is read from the * underlying iterable and added to the buffer. * * This is useful for maintaining a constant numb

(capacity: number)

   * @returns {Stream} A new Stream that gets its values from this Stream.
   */
  buffer(capacity: number) {
    return new Stream((function* () {
      const b = [];
      try {
        // @ts-ignore
        for (const v of this) {
          Promise.resolve(v).catch(() => {}); // Suppress unhandled rejection errors.
          // Note: V8 has good Array push+shift optimization.
          while (b.length >= capacity) yield b.shift();
          b.push(v);
        }
        while (b.length) yield b.shift();
      } finally {
        for (const v of b) Promise.resolve(v).then(() => {}); // Un-suppress unhandled rejections.
      }
    }).call(this));
  }

  /**
   * Like Array.map().