Function isLeftClickEvent

docs/lib/ReactRouter.js:1758–1760

(event)

	var oneOfType = _React$PropTypes.oneOfType;

	function isLeftClickEvent(event) {
	  return event.button === 0;
	}

	function isModifiedEvent(event) {
	  return !!(event.metaKey || event.altKey || event.ctrlKey || event.shiftKey);