Using mixins with Ember-cli?

Instead of adding ../ (or even worse ../../../) into your imports, you can go to your config/environment.js and check for the property modulePrefix. Let's say the prefix is app-client.

Then, you can import by using import UIListen from 'app-client/mixins/ui-listener'; instead. Absolute works best if you are in a "deep" subroute, etc.

I don't know how do you export your mixin but this should work:

in mixins/ui-listener.js:

import Ember from 'ember';

export default Ember.Mixin.create({
 //some stuff
});

in components/my-component.js:

import Ember from 'ember';
import UIListenerMixin from '../mixins/ui-listener';

export default Ember.Component.extend(UIListenerMixin, {
 // some stuff
});