function isEventSupported()

in packages/fbjs/src/__forks__/isEventSupported.js [38:59]

• 17 lines of code
• 8 McCabe index (conditional complexity)

function isEventSupported(eventNameSuffix, capture) {
  if (!ExecutionEnvironment.canUseDOM ||
      capture && !('addEventListener' in document)) {
    return false;
  }

  var eventName = 'on' + eventNameSuffix;
  var isSupported = eventName in document;

  if (!isSupported) {
    var element = document.createElement('div');
    element.setAttribute(eventName, 'return;');
    isSupported = typeof element[eventName] === 'function';
  }

  if (!isSupported && useHasFeature && eventNameSuffix === 'wheel') {
    // This is the only way to test support for the `wheel` event in IE9+.
    isSupported = document.implementation.hasFeature('Events.wheel', '3.0');
  }

  return isSupported;
}