Class Engine

The goal of initializers should be to register dependencies and injections. This phase runs once. Because these initializers may load code, they are allowed to defer application readiness and advance it. If you need to access the container or store you should use an InstanceInitializer that will be run after all initializers and therefore after all code is loaded and the app is ready.

Initializer receives an object which has the following attributes: name, before, after, initialize. The only required attribute is initialize, all others are optional.

• name allows you to specify under which name the initializer is registered. This must be a unique name, as trying to register two initializers with the same name will result in an error.

import { debug } from '@ember/debug';

export function initialize() {
  debug('Running namedInitializer!');
}

export default {
  name: 'named-initializer',
  initialize
};

• before and after are used to ensure that this initializer is ran prior or after the one identified by the value. This value can be a single string or an array of strings, referencing the name of other initializers.

An example of ordering initializers, we create an initializer named first:

import { debug } from '@ember/debug';

export function initialize() {
  debug('First initializer!');
}

export default {
  name: 'first',
  initialize
};

// DEBUG: First initializer!

We add another initializer named second, specifying that it should run after the initializer named first:

import { debug } from '@ember/debug';

export function initialize() {
  debug('Second initializer!');
}

export default {
  name: 'second',
  after: 'first',
  initialize
};

// DEBUG: First initializer!
// DEBUG: Second initializer!

Afterwards we add a further initializer named pre, this time specifying that it should run before the initializer named first:

import { debug } from '@ember/debug';

export function initialize() {
  debug('Pre initializer!');
}

export default {
  name: 'pre',
  before: 'first',
  initialize
};

// DEBUG: Pre initializer!
// DEBUG: First initializer!
// DEBUG: Second initializer!

Finally we add an initializer named post, specifying it should run after both the first and the second initializers:

import { debug } from '@ember/debug';

export function initialize() {
  debug('Post initializer!');
}

export default {
  name: 'post',
  after: ['first', 'second'],
  initialize
};

// DEBUG: Pre initializer!
// DEBUG: First initializer!
// DEBUG: Second initializer!
// DEBUG: Post initializer!

• initialize is a callback function that receives one argument, application, on which you can operate.

Example of using application to register an adapter:

import ApiAdapter from '../utils/api-adapter';

export function initialize(application) {
  application.register('api-adapter:main', ApiAdapter);
}

export default {
  name: 'post',
  after: ['first', 'second'],
  initialize
};

Instance initializers run after all initializers have run. Because instance initializers run after the app is fully set up. We have access to the store, container, and other items. However, these initializers run after code has loaded and are not allowed to defer readiness.

Instance initializer receives an object which has the following attributes: name, before, after, initialize. The only required attribute is initialize, all others are optional.

• name allows you to specify under which name the instanceInitializer is registered. This must be a unique name, as trying to register two instanceInitializer with the same name will result in an error.

import { debug } from '@ember/debug';

export function initialize() {
  debug('Running named-instance-initializer!');
}

export default {
  name: 'named-instance-initializer',
  initialize
};

• before and after are used to ensure that this initializer is ran prior or after the one identified by the value. This value can be a single string or an array of strings, referencing the name of other initializers.

• See Ember.Application.initializer for discussion on the usage of before and after.

Example instanceInitializer to preload data into the store.

import $ from 'jquery';

export function initialize(application) {
    var userConfig, userConfigEncoded, store;
    // We have a HTML escaped JSON representation of the user's basic
    // configuration generated server side and stored in the DOM of the main
    // index.html file. This allows the app to have access to a set of data
    // without making any additional remote calls. Good for basic data that is
    // needed for immediate rendering of the page. Keep in mind, this data,
    // like all local models and data can be manipulated by the user, so it
    // should not be relied upon for security or authorization.

    // Grab the encoded data from the meta tag
    userConfigEncoded = $('head meta[name=app-user-config]').attr('content');

    // Unescape the text, then parse the resulting JSON into a real object
    userConfig = JSON.parse(unescape(userConfigEncoded));

    // Lookup the store
    store = application.lookup('service:store');

    // Push the encoded JSON into the store
    store.pushPayload(userConfig);
}

export default {
  name: 'named-instance-initializer',
  initialize
};