Function writeOrBuffer

lib/internal/streams/writable.js:548–585

(stream, state, chunk, encoding, callback)

// in the queue, and wait our turn.  Otherwise, call _write
// If we return false, then we need a drain event, so set that flag.
function writeOrBuffer(stream, state, chunk, encoding, callback) {
  const len = (state[kState] & kObjectMode) !== 0 ? 1 : chunk.length;

  state.length += len;

  if ((state[kState] & (kWriting | kErrored | kCorked | kConstructed)) !== kConstructed) {
    if ((state[kState] & kBuffered) === 0) {
      state[kState] |= kBuffered;
      state[kBufferedValue] = [];
    }

    state[kBufferedValue].push({ chunk, encoding, callback });
    if ((state[kState] & kAllBuffers) !== 0 && encoding !== 'buffer') {
      state[kState] &= ~kAllBuffers;
    }
    if ((state[kState] & kAllNoop) !== 0 && callback !== nop) {
      state[kState] &= ~kAllNoop;
    }
  } else {
    state.writelen = len;
    if (callback !== nop) {
      state.writecb = callback;
    }
    state[kState] |= kWriting | kSync | kExpectWriteCb;
    stream._write(chunk, encoding, state.onwrite);
    state[kState] &= ~kSync;
  }

  const ret = state.length < state.highWaterMark || state.length === 0;

  if (!ret) {
    state[kState] |= kNeedDrain;
  }

  // Return false if errored or destroyed in order to break
  // any synchronous while(stream.write(data)) loops.
  return ret && (state[kState] & (kDestroyed | kErrored)) === 0;
}

function doWrite(stream, state, writev, len, chunk, encoding, cb) {
  state.writelen = len;