Method readFrom

io/buffer.ts:428–450

* Reads data from `r` until EOF (`null`) and appends it to the buffer, * growing the buffer as needed. It resolves to the number of bytes read. * If the buffer becomes too large, `.readFrom()` will reject with an error. * * Based on Go Lang's * {@link https://golang.org/pkg/bytes/#Buf

(r: Reader)

   * @returns The number of bytes read.
   */
  async readFrom(r: Reader): Promise<number> {
    let n = 0;
    const tmp = new Uint8Array(MIN_READ);
    while (true) {
      const shouldGrow = this.capacity - this.length < MIN_READ;
      // read into tmp buffer if there's not enough room
      // otherwise read directly into the internal buffer
      const buf = shouldGrow
        ? tmp
        : new Uint8Array(this.#buf.buffer, this.length);

      const nread = await r.read(buf);
      if (nread === null) {
        return n;
      }

      // write will grow if needed
      if (shouldGrow) this.writeSync(buf.subarray(0, nread));
      else this.#reslice(this.length + nread);

      n += nread;
    }
  }

  /** Reads data from `r` until EOF (`null`) and appends it to the buffer,
   * growing the buffer as needed. It returns the number of bytes read. If the