javascript - 如何在 javascript 中使用 Object.deliverChangeRecords 方法

Question

我了解如何使用 Object.observe() 和 Object.getNotifier(obj).notify 或 Object.getNotifier(obj).performChange，但如何使用 Object.deliverChangeRecords()

Answer 1

The point of Object.deliverChangeRecords is to get synchronous delivery to the function that is listening to the mutations.

http://www.danyow.net/object-deliverchangerecords/

这是一个运行示例，演示了使用和不使用 deliverChangeRecords 的事件序列:

var output = document.getElementById('output');

function runTest(useDeliver) {
  var obj = {};

  output.textContent = '';
 
  function handleChange(records) {
    output.textContent += 'CHANGE DELIVERED\n';
  }
  
  Object.observe(obj, handleChange);
  
  output.textContent += '1\n';
  
  obj.a = 'b';
  
  output.textContent += '2\n';
  
  if (useDeliver) {
    Object.deliverChangeRecords(handleChange);
  }
  
  output.textContent += '3\n';
  
}

<button onclick="runTest(true)">With deliverChangeRecords</button>
<button onclick="runTest(false)">Without deliverChangeRecords</button>
<pre id="output"></pre>