Function push

lib/assets/react-source/development/react.js:3041–3045

(heap, node)

	}

	function push(heap, node) {
	  var index = heap.length;
	  heap.push(node);
	  siftUp(heap, node, index);
	}
	function peek(heap) {
	  var first = heap[0];
	  return first === undefined ? null : first;