new.js

import Ember from 'ember';

export default Ember.Controller.extend({
  searchText: null,

  searchResults: [],

  updateResults: function() {
    var self = this;
    var searchText = self.get('searchText');
    if (!searchText) { return; }

    var encoded = encodeURIComponent(searchText);
    Ember.$.get("/your/autocomplete/path?term=" + encoded, function(json) {
      self.set('searchResults', json);
    });
  }.property('searchText')
});