React：调用最终渲染方法之前的异步调用以更新状态

Background: I'm trying to use React to update some UI elements based on a json response from some webservice, however because I have a lot of elements to be rendered, I'm trying to lessen bandwidth by only pulling json if an element's HashCode is updated. In the context of my application I cannot update the asynchronous behavior of my ajax calls. What would be the right way to force the update to my elements only after the asynchronous call is completed? I'm trying to use React to update s