Aurelia停止HTTP请求重载

Question

I'm using Aurelia and have multiple promises calling my API. If I continually click the button to fire the promises over and over and over again the back end will timeout. How can I stop/halt the promises I am firing and just get the newest one so as to not over work the API and cause a timeout?

Answer 1

This is not specific to aurelia, it happens with any asynchronous event implementation.

1. When you click on a button, the event handler is called.
2. The event handler sends an asynchronous AJAX request to your server. Because it's async, your code and your application continues to run while the request is happening.
3. User can click again on the button and a second AJAX request can be sent at the same time, assuming that you click faster than requests complete.
4. To make it worse, concurrent requests may even complete out-of-order (ie a later request completes before a former). Your code should be prepared to handle that properly.

If you don't want this behaviour, it is up to you to prevent the user from submitting again until the AJAX request completes. For example you could:

• Disable the button when sending the request; or
• Display a modal "loading" screen / spinner to prevent any interaction with the application while the request is in flight.

Note that giving user feedback is good UX anyway. A network request might be delayed for a whole lot of reasons and it is a good idea to give some feedback to let him know that something is happening.