Readable.prototype.read = function()

in digital-shadow/demo-car/js/aws-iot/aws-iot.js [12917:12989]

• 54 lines of code
• 26 McCabe index (conditional complexity)

Readable.prototype.read = function(n) {
  var state = this._readableState;
  state.calledRead = true;
  var nOrig = n;
  var ret;

  if (typeof n !== 'number' || n > 0)
    state.emittedReadable = false;

  if (n === 0 &&
      state.needReadable &&
      (state.length >= state.highWaterMark || state.ended)) {
    emitReadable(this);
    return null;
  }

  n = howMuchToRead(n, state);

  if (n === 0 && state.ended) {
    ret = null;

    if (state.length > 0 && state.decoder) {
      ret = fromList(n, state);
      state.length -= ret.length;
    }

    if (state.length === 0)
      endReadable(this);

    return ret;
  }


  var doRead = state.needReadable;

  if (state.length - n <= state.highWaterMark)
    doRead = true;

  if (state.ended || state.reading)
    doRead = false;

  if (doRead) {
    state.reading = true;
    state.sync = true;
    if (state.length === 0)
      state.needReadable = true;
    this._read(state.highWaterMark);
    state.sync = false;
  }

  if (doRead && !state.reading)
    n = howMuchToRead(nOrig, state);

  if (n > 0)
    ret = fromList(n, state);
  else
    ret = null;

  if (ret === null) {
    state.needReadable = true;
    n = 0;
  }

  state.length -= n;

  if (state.length === 0 && !state.ended)
    state.needReadable = true;

  if (state.ended && !state.endEmitted && state.length === 0)
    endReadable(this);

  return ret;
};