description

# MutationObserver constructor Null safety

MutationObserver(

1. MutationCallback callback

)

## Implementation

    factory MutationObserver(MutationCallback callback) {
      // Dummy statement to mark types as instantiated.
      JS('MutationObserver|MutationRecord', '0');

      return JS(
          'MutationObserver',
          'new(window.MutationObserver||window.WebKitMutationObserver||'
              'window.MozMutationObserver)(#)',
          convertDartClosureToJS(_wrapBinaryZone(callback), 2));
    }