description

# addEventListener method Null safety

void addEventListener (

1. String type,
2. EventListener? listener,
3. [bool? useCapture]

)

## Implementation

    void addEventListener(String type, EventListener? listener,
        [bool? useCapture]) {
      // TODO(leafp): This check is avoid a bug in our dispatch code when
      // listener is null.  The browser treats this call as a no-op in this
      // case, so it's fine to short-circuit it, but we should not have to.
      if (listener != null) {
        _addEventListener(type, listener, useCapture);
      }
    }