transform

Source

dynamic transform(
    dynamic /* Stream< dynamic > | Future< dynamic > | EventEmitter< dynamic > */ obj) {
  if (_obj == null) {
    if (obj != null) {
      this._subscribe(obj);
    }
    this._latestReturnedValue = this._latestValue;
    return this._latestValue;
  }
  if (!identical(obj, this._obj)) {
    this._dispose();
    return this.transform(obj);
  }
  if (identical(this._latestValue, this._latestReturnedValue)) {
    return this._latestReturnedValue;
  } else {
    this._latestReturnedValue = this._latestValue;
    return WrappedValue.wrap(this._latestValue);
  }
}