Method frame

lib/sender.js:79–173

* Frames a piece of data according to the HyBi WebSocket protocol. * * @param {(Buffer|String)} data The data to frame * @param {Object} options Options object * @param {Boolean} [options.fin=false] Specifies whether or not to set the * FIN bit * @param {Function} [options.gene

(data, options)

   * @public
   */
  static frame(data, options) {
    let mask;
    let merge = false;
    let offset = 2;
    let skipMasking = false;

    if (options.mask) {
      mask = options.maskBuffer || maskBuffer;

      if (options.generateMask) {
        options.generateMask(mask);
      } else {
        if (randomPoolPointer === RANDOM_POOL_SIZE) {
          /* istanbul ignore else  */
          if (randomPool === undefined) {
            //
            // This is lazily initialized because server-sent frames must not
            // be masked so it may never be used.
            //
            randomPool = Buffer.alloc(RANDOM_POOL_SIZE);
          }

          randomFillSync(randomPool, 0, RANDOM_POOL_SIZE);
          randomPoolPointer = 0;
        }

        mask[0] = randomPool[randomPoolPointer++];
        mask[1] = randomPool[randomPoolPointer++];
        mask[2] = randomPool[randomPoolPointer++];
        mask[3] = randomPool[randomPoolPointer++];
      }

      skipMasking = (mask[0] | mask[1] | mask[2] | mask[3]) === 0;
      offset = 6;
    }

    let dataLength;

    if (typeof data === 'string') {
      if (
        (!options.mask || skipMasking) &&
        options[kByteLength] !== undefined
      ) {
        dataLength = options[kByteLength];
      } else {
        data = Buffer.from(data);
        dataLength = data.length;
      }
    } else {
      dataLength = data.length;
      merge = options.mask && options.readOnly && !skipMasking;
    }

    let payloadLength = dataLength;

    if (dataLength >= 65536) {
      offset += 8;
      payloadLength = 127;