Ember.js: declaring a computed property/observer with ES7 decorators - http://blog.ksol.fr/ember-js-declaring-computed-property-and-observers/

gistfile1.js

import computed, { observes } from 'ember-computed-decorators';

export default Ember.Object.extend({
  firstName: "Bob",
  lastName: "Jones",
  
  @computed('firstName', 'lastName')
  fullName: function(firstName, lastName) {
    return `${firstName} ${lastName}`;
  },
  
  @observes('fullName')
  nameHasChanged: function(fullName) {
    console.log(`name has changed! Now it is ${'fullName'}`);
  }
});