How to tell if page is loading in theme component / widget?

[hawm]

You may try queueRerender() instead of scheduleRerender()

@eviltrout

Bindings and Rerendering Content

If you’ve been working with Ember for a while, you might be wondering how the widgets know when they need to be rerendered since they aren’t using Ember’s bindings or observers system. In fact, this is one of the big trade offs widgets make: in Ember’s view rendering this is handled transparently for you, but with Widgets we assume the widget only needs to be re-rendered when you interact with them.

Widgets are rerendered when:

• A user clicks on them
• After any actions are triggered
• If an action returns a promise, after that promise has resolved

The above cases count for the vast majority of the times when Discourse needs to rerender a widget. However, if you have an edge case, a widget can rerender itself by calling this.queueRerender() .

Render calls are coalesced on the Ember Run Loop , so don’t be afraid to call this.queueRerender() multiple times in the same event loop – the widget will only render one time for all the changes you’ve queued.