How to Handle 'iron-ajax` Timeout

Question

The iron-ajax web component has a timeout property, but after reading through the components code on GitHub I am not sure how to handle it.

<iron-ajax id="ajax"
  handle-as="json"
  last-response="{{response}}"
  method="get"
  timeout="5000"
  url="https://api.domain.com/">
</iron-ajax>

Does it fire an event?

Is it observable?

How can I run a function when a request reaches its timeout limit?

Answer 1

The timeout property on iron-ajax is the number of milliseconds a request can take before automatically being terminated. As this timeout is an error the iron-ajax element will fire an error event which you can use to call a function when triggered. For instance:

<iron-ajax id="ajax"
  handle-as="json"
  last-response="{{response}}"
  method="get"
  timeout="5000"
  url="https://api.domain.com/"
  on-error="_showError">
</iron-ajax>

...

class MyElement extends Polymer.Element {
  static get is() { return 'my-ele'; }

  ...

  _showError(event, request) {
    // display error message
  }
}