Function clearBuffer

lib/internal/streams/writable.js:744–796

(stream, state)

// If there's something in the buffer waiting, then process it.
function clearBuffer(stream, state) {
  if ((state[kState] & (kDestroyed | kBufferProcessing | kCorked | kBuffered | kConstructed)) !==
      (kBuffered | kConstructed)) {
    return;
  }

  const objectMode = (state[kState] & kObjectMode) !== 0;
  const { [kBufferedValue]: buffered, bufferedIndex } = state;
  const bufferedLength = buffered.length - bufferedIndex;

  if (!bufferedLength) {
    return;
  }

  let i = bufferedIndex;

  state[kState] |= kBufferProcessing;
  if (bufferedLength > 1 && stream._writev) {
    state.pendingcb -= bufferedLength - 1;

    const callback = (state[kState] & kAllNoop) !== 0 ? nop : (err) => {
      for (let n = i; n < buffered.length; ++n) {
        buffered[n].callback(err);
      }
    };
    // Make a copy of `buffered` if it's going to be used by `callback` above,
    // since `doWrite` will mutate the array.
    const chunks = (state[kState] & kAllNoop) !== 0 && i === 0 ?
      buffered : ArrayPrototypeSlice(buffered, i);
    chunks.allBuffers = (state[kState] & kAllBuffers) !== 0;

    doWrite(stream, state, true, state.length, chunks, '', callback);

    resetBuffer(state);
  } else {
    do {
      const { chunk, encoding, callback } = buffered[i];
      buffered[i++] = null;
      const len = objectMode ? 1 : chunk.length;
      doWrite(stream, state, false, len, chunk, encoding, callback);
    } while (i < buffered.length && (state[kState] & kWriting) === 0);

    if (i === buffered.length) {
      resetBuffer(state);
    } else if (i > 256) {
      buffered.splice(0, i);
      state.bufferedIndex = 0;
    } else {
      state.bufferedIndex = i;
    }
  }
  state[kState] &= ~kBufferProcessing;
}

Writable.prototype._write = function(chunk, encoding, cb) {
  if (this._writev) {