Function destroy

lib/internal/streams/destroy.js:49–88

(err, cb)

// Backwards compat. cb() is undocumented and unused in core but
// unfortunately might be used by modules.
function destroy(err, cb) {
  const r = this._readableState;
  const w = this._writableState;
  // With duplex streams we use the writable side for state.
  const s = w || r;

  if (
    (w && (w[kState] & kDestroyed) !== 0) ||
    (r && (r[kState] & kDestroyed) !== 0)
  ) {
    if (typeof cb === 'function') {
      cb();
    }

    return this;
  }


  // We set destroyed to true before firing error callbacks in order
  // to make it re-entrance safe in case destroy() is called within callbacks
  checkError(err, w, r);

  if (w) {
    w[kState] |= kDestroyed;
  }
  if (r) {
    r[kState] |= kDestroyed;
  }

  // If still constructing then defer calling _destroy.
  if ((s[kState] & kConstructed) === 0) {
    this.once(kDestroy, function(er) {
      _destroy(this, aggregateTwoErrors(er, err), cb);
    });
  } else {
    _destroy(this, err, cb);
  }

  return this;
}

function _destroy(self, err, cb) {
  let called = false;