Function constructSelectEvent

code/composition/public/app.js:6788–6813

* Poll selection to see whether it's changed. * * @param {object} nativeEvent * @return {?SyntheticEvent}

(nativeEvent, nativeEventTarget)

 * @return {?SyntheticEvent}
 */
function constructSelectEvent(nativeEvent, nativeEventTarget) {
  // Ensure we have the right element, and that the user is not dragging a
  // selection (this matches native `select` event behavior). In HTML5, select
  // fires only on input and textarea thus if there's no focused element we
  // won't dispatch.
  if (mouseDown || activeElement$1 == null || activeElement$1 !== getActiveElement()) {
    return null;
  }

  // Only fire when selection has actually changed.
  var currentSelection = getSelection(activeElement$1);
  if (!lastSelection || !shallowEqual(lastSelection, currentSelection)) {
    lastSelection = currentSelection;

    var syntheticEvent = SyntheticEvent$1.getPooled(eventTypes$3.select, activeElementInst$1, nativeEvent, nativeEventTarget);

    syntheticEvent.type = 'select';
    syntheticEvent.target = activeElement$1;

    accumulateTwoPhaseDispatches(syntheticEvent);

    return syntheticEvent;
  }

  return null;
}

/**
 * This plugin creates an `onSelect` event that normalizes select events