How to make an Ember module resolve as another one

12 February 2016

I wanted to write another short, and hopefully useful, post just as I did recently for binding the style attribute.

No configuration is simpler than no configuration

About a month ago I was working to add authorization to the Rock and Roll with Ember application. I used my favorite addon, Torii, to help with that and opted to do the authorization via the google-oauth2-bearer provider. To restore the session, Torii looks up the application (Torii) adapter, but the session initialization and closing code used the google-oauth2-bearer adapter. So I had two separate files, which I was not happy about and I did not want to merge everything into the application adapter, as it does not give a hint about its contents then.

My idea was to make it possible to use another adapter to restore the session from, via a configuration option. Matthew Beale hinted at a solution that removes the need for a configuration option and since I haven't seen this before, I want to share it with you.

Import from target module, then reexport

The Ember resolver is the piece that maps qualified full names (like route:blog or controller:bands) to module names.

In my case, Torii makes the resolver look up torii-adapter:application to fetch the session from and I wanted this to be resolved to torii-adapter:google-oauth2-bearer. In the Ember CLI project, that is equivalent of having the app/torii-adapters/application.js file export what is exported by app/torii-adapters/google-oauth2-bearer.js.

When phrased like this, the solution is near and I am somewhat embarrassed it took me a few attempts to arrive at this.

So the solution is to import in app/torii-adapters/application.js what app/torii-adapters/google-oauth2-bearer.js exports and then reexport it:

// app/torii-adapters/application.js
import GoogleOAuth2BearerAdapter from './google-oauth2-bearer';

export default GoogleOAuth2BearerAdapter;

// app/torii-adapters/google-oauth2-bearer.js
export default Ember.Object.extend({
  (...)
});

Voila, we have "tricked" the resolver without adding any configuration (and thus complexity) to the addon.