Function _write

lib/internal/streams/writable.js:450–502

(stream, chunk, encoding, cb)

};

function _write(stream, chunk, encoding, cb) {
  const state = stream._writableState;

  if (cb == null || typeof cb !== 'function') {
    cb = nop;
  }

  if (chunk === null) {
    throw new ERR_STREAM_NULL_VALUES();
  }

  if ((state[kState] & kObjectMode) === 0) {
    if (!encoding) {
      encoding = (state[kState] & kDefaultUTF8Encoding) !== 0 ? 'utf8' : state.defaultEncoding;
    } else if (encoding !== 'buffer' && !Buffer.isEncoding(encoding)) {
      throw new ERR_UNKNOWN_ENCODING(encoding);
    }

    if (typeof chunk === 'string') {
      if (encoding === 'buffer') {
        throw new ERR_UNKNOWN_ENCODING(encoding);
      }
      if ((state[kState] & kDecodeStrings) !== 0) {
        chunk = Buffer.from(chunk, encoding);
        encoding = 'buffer';
      }
    } else if (chunk instanceof Buffer) {
      encoding = 'buffer';
    } else if (Stream._isArrayBufferView(chunk)) {
      chunk = Stream._uint8ArrayToBuffer(chunk);
      encoding = 'buffer';
    } else {
      throw new ERR_INVALID_ARG_TYPE(
        'chunk', ['string', 'Buffer', 'TypedArray', 'DataView'], chunk);
    }
  }

  let err;
  if ((state[kState] & kEnding) !== 0) {
    err = new ERR_STREAM_WRITE_AFTER_END();
  } else if ((state[kState] & kDestroyed) !== 0) {
    err = new ERR_STREAM_DESTROYED('write');
  }

  if (err) {
    process.nextTick(cb, err);
    errorOrDestroy(stream, err, true);
    return err;
  }

  state.pendingcb++;
  return writeOrBuffer(stream, state, chunk, encoding, cb);
}

Writable.prototype.write = function(chunk, encoding, cb) {
  if (encoding != null && typeof encoding === 'function') {