Function addChunk

lib/internal/streams/readable.js:557–586

(stream, state, chunk, addToFront)

}

function addChunk(stream, state, chunk, addToFront) {
  if ((state[kState] & (kFlowing | kSync | kDataListening)) === (kFlowing | kDataListening) && state.length === 0) {
    // Use the guard to avoid creating `Set()` repeatedly
    // when we have multiple pipes.
    if ((state[kState] & kMultiAwaitDrain) !== 0) {
      state.awaitDrainWriters.clear();
    } else {
      state.awaitDrainWriters = null;
    }

    state[kState] |= kDataEmitted;
    stream.emit('data', chunk);
  } else {
    // Update the buffer info.
    state.length += (state[kState] & kObjectMode) !== 0 ? 1 : chunk.length;
    if (addToFront) {
      if (state.bufferIndex > 0) {
        state.buffer[--state.bufferIndex] = chunk;
      } else {
        state.buffer.unshift(chunk); // Slow path
      }
    } else {
      state.buffer.push(chunk);
    }

    if ((state[kState] & kNeedReadable) !== 0)
      emitReadable(stream);
  }
  maybeReadMore(stream, state);
}

Readable.prototype.isPaused = function() {
  const state = this._readableState;