Ember.js
is an open-source JavaScript web framework for building modern web applications, utilizing a component-service pattern. It includes everything you need to build rich UIs that work on any device. It does so by providing developers many features that are essential to manage complexity in modern single-page web applications, as well as an integrated development toolkit that enables rapid iteration.Ember.js
was developed by Yehuda Katz in initially released 8 December 2011. Now upgraded versions are take care by Ember core team. npm install -g ember-cli
addon
." An addon provides a way to write reusable code, share components and styling, extend the build tooling, and more—all with minimal configuration. You can visit Ember Observer to search addons.v3.x
, Ember apps include the ember-auto-import
dependency, which enables importing npm packages directly. For example, if you want to use highcharts
in your application, you can install and import it without any other configuration. Be sure to visit the ember-auto-import documentation for more advanced usage!Ember CLI
via npm
, you will have access to a new ember
command in your terminal. You can use the ember new
command to create a new application.ember new ember-quickstart --lang en
ember-quickstart
and set up a new Ember application inside of it. The --lang en
option sets the app's primary language to English to help improve accessibility. Out of the box, your application will include:cd
into the application directory ember-quickstart
and start the development server by typing:cd ember-quickstart
ember serve
Livereload server on http://localhost:7020
Serving on http://localhost:4200/
Ctrl-C
in your terminal.)http://localhost:4200
in your browser of choice. You should see an Ember welcome page.Ember.js
doesn't require server requests to perform its task.ember-quickstart
directory :ember generate route scientists
installing route
create app/routes/scientists.js
create app/templates/scientists.hbs
updating router
add route scientists
installing route-test
create tests/unit/routes/scientists-test.js
/scientists
.Route
object that fetches the model used by that template.app/router.js
).app/templates/scientists.hbs
and add the following HTML :{{page-title "Scientists"}}
<h2>List of Scientists</h2>
http://localhost:4200/scientists
. You should see the <h2>
we put in the scientists.hbs template right below the <h1>
from our application.hbs
template.{{outlet}}
directive.app/routes/scientists.js
.model()
method to the Route
:import Route from '@ember/routing/route';
export default class ScientistsRoute extends Route {
model() {
return ['Marie Curie', 'Mae Jemison', 'Albert Hofmann'];
}
}
model()
method, you return whatever data you want to make available to the template. If you need to fetch data asynchronously, the model()
method supports any library that uses JavaScript Promises.scientists
template and add the following code to loop through the array and print it :<h2>List of Scientists</h2>
<ul>
{{#each @model as |scientist|}}
<li>{{scientist}}</li>
{{/each}}
</ul>
each
item in the array we provided from the model()
hook. Ember will render the block contained inside the {{#each}}...{{/each}}
helper once for each item (each scientist in our case) in the array. The item (the scientist) that is being rendered currently will be made available in the scientist variable, as denoted by as |scientist|
in the each helper.<li>
element corresponding to each scientist in the array inside the <ul>
unordered list.Ember.Route.extend ({
model(parameter) {
//code block
}
});
Router.map(function() {
this.route('linkpage', { path: 'identifiers' });
});
Ember.Route.extend ({
model() {
return Ember.RSVP.hash({
//code block
})
}
});
Ember.js
application is based on MVC (Model, View, Controller) pattern.Ember.js
, instead of majority of your application’s logic living on the server, an ember.js
application downloads everything it required to run in the initial page load. So user does not have to load a new page while using the app and UI will responds quickly. The advantage of this architecture is that your web application uses the same REST API
as your native App. Em.View
class, you have to create an oject in your JavaScript to define a view. You can declare your functions and variables inside that.script {{ #view App.ViewName}}
Ember.js
are Rest
, JSON
, LS Adapter
, and the latter deals with local storage or when data needs to be stored in low. Ember.js
, we can call the extend()
method on Ember.Object
to define a new ember
class.App.Person = Ember.Object.extend({
say: function(thing) {
alert(thing);
}
});
App.Person
class with a say()
method.extend()
method. See the following example if you want to create a subclass of Ember's built-in Ember.View
class.App.PersonView = Ember.View.extend({
tagName: 'li',
classNameBindings: ['isAdministrator']
});
special _super()
method.App.Person = Ember.Object.extend({
say: function(thing) {
var name = this.get('name');
alert(name + " says: " + thing);
}
});
AppApp.Soldier = App.Person.extend({
say: function(thing) {
this._super(thing + ", sir!");
}
});
var sam = App.Soldier.create({
name: "Free Time Leaarn"
});
sam.say("Reporting"); // alerts "Free Time Leaarn says: Reporting, sir!"
Ember.js
, a service is a long-lived Ember object that can be available in different parts of your application. The following syntax is used to create the Ember.js
service."ember. Service"​
Following is a list of some examples of Ember.js
services :inject
it either in an initializer or use the following syntax :"ember.Inject"
ember generate service service_name;
HTML
. These are called blocks
. Here's an example that provides a component with the implicit
default block.<ExampleComponent>
This is the default <b>block content</b> that will
replace `{{yield}}` (or `{{yield to="default"}}`)
in the `ExampleComponent` template.
</ExampleComponent>
<ExampleComponent>
<:default>
This is the default <b>block content</b> that will
replace `{{yield}}` (or `{{yield to="default"}}`)
in the `ExampleComponent` template.
</:default>
</ExampleComponent>
HTML
, modifiers
, and other components within the block
.Helper functions
are JavaScript functions that you can call from your template.<Message::Avatar
@title={{@avatarTitle}}
@initial={{@avatarInitial}}
@isActive={{@userIsActive}}
class={{if @isCurrentUser "current-user"}}
/>
<section>
<Message::Username
@name={{@username}}
@localTime={{@userLocalTime}}
/>
{{yield}}
</section>
<Message
@username="Tomster"
@userIsActive={{true}}
@userLocalTime="4:56pm"
@avatarTitle="Tomster's avatar"
@avatarInitial="T"
>
<p>
Hey Zoey, have you had a chance to look at the EmberConf
brainstorming doc I sent you?
</p>
</Message>
<Message>
component, we can see that some of the arguments are fairly repetitive. Both @avatarTitle
and @avatarInitial
are based on the user's @username
, but the title has more text, and the initial is only the first letter of the name. We'd rather just pass a username to the <Message>
component and compute the value of the title and initial.@username
argument and calculate the title and initial.classes
instead.app/helpers/substring.js
:import { helper } from '@ember/component/helper';
import Helper from '@ember/component/helper';
function substring([string], { start, length }) {
export default class Substring extends Helper {
compute([string], { start, end }) {
return string.substring(start || 0, end);
}
}
Class helpers
are useful when the helper logic is fairly complicated, requires fine-grained control of the helper lifecycle, or is stateful (we'll be discussing state in the next chapter).<Input>
<Textarea>
<input>
or <textarea>
elements. In contrast to the native elements, <Input>
and <Textarea>
automatically update the state of their bound values.<Input>
: We mentioned that the built-in components are similar in HTML markup to their native counterparts.<label for="user-question">Ask a question about Ember:</label>
<Input
id="user-question"
@type="text"
@value="How do text fields work?"
/>
<Textarea>
: The following example shows how to bind this.userComment
to a text area's value.<label for="user-comment">Comment:</label>
<Textarea
id="user-comment"
@value={{this.userComment}}
rows="6"
cols="80"
/>
<Textarea>
: With the exception of @value
argument, you can use any attribute that <textarea>
natively supports.error
and loading
substates exist as a part of each route, so they should not be added to your router.js
file. To utilize a substate, the route, controller, and template may be optionally defined as desired.loading
substates : During the beforeModel
, model
, and afterModel
hooks, data may take some time to load. Technically, the router pauses the transition until the promises returned from each hook fulfill.app/router.js
:Router.map(function() {
this.route('slow-model');
});
app/routes/slow-model.js
:import Route from '@ember/routing/route';
import { service } from '@ember/service';
export default class SlowModelRoute extends Route {
@service store;
model() {
return this.store.findAll('slow-model');
}
}
error
substates : Ember provides an analogous approach to loading
substates in the case of errors
encountered during a transition.loading
event handlers are implemented, the default error
handlers will look for an appropriate error substate to enter, if one can be found.app/router.js
:Router.map(function() {
this.route('articles', function() {
this.route('overview');
});
});
loading
substate, on a thrown error or rejected promise returned from the articles.overview
route's model
hook (or beforeModel
or afterModel
) Ember will look for an error template or route in the following order :articles.overview-error
articles.error
or articles-error
error
or application-error
Route
and Router
both are different terms in Ember.js
.Ember.js
package are :Ember.js
, project structure is also called directory structure. It contains the following files and directories :I-app
: It contains folders and files for models, components, routes, templates, and styles.I-bower_components/ bower.json
: It is a dependency management tool which is used in Ember CLI to manage front-end plugins and component dependencies.I-config
: It contains the environment.js which controls configure settings for your app.I-dist
: It contains the created output files when we build our app for deployment.I-node_nodules/package.json
: Directory and files are from npm. Npm is the package manager for node.js.Public
: The public directory contains assets such as image and fonts.Vendor
: This directory specifies a location where front-end dependencies that are not managed by Bower go.Tests/testem.js
: Automated tests for our app go in the test folder, and testing is configured in testem.js.Tmp
: Ember CLI temporary files live here.Ember-cli-build.js
: This file describes how Ember CLI should build our app.fixtures
. However, it is necessary that applications must be connected with each other. The application adapter is to be made the extension of Ds.Fixture
. For communication purposes, the adapters can be deployed easily. At the last, the file is to be updated to the model todo.js
Enumerable
that generally contains child objects. Using the operator Ember. Enumerable API, it is possible to work with these child objects
. However, in some applications that have complex sizes, the native JavaScript array is the commonly used enumerable. observing
any property which also includes computed properties. Observers are something which contains the behavior that reacts to the changes made in other properties. Observers are used when we need to perform some behavior after binding has finished synchronizing. New ember developers often use observers. Observers are mostly used within the ember framework and for that; computed properties are the appropriate solution. ember.observer
" Observers in ember
are synchronous
. They fire as soon as they observe a change in the properties. So, because of this, it is easy to introduce bugs where properties are not yet synchronized. model
is a class that defines the properties and behavior of the data that you present to the user. Anything that the user expects to see if they leave your app and come back later (or if they refresh the page) should be represented by a model
.Model
. This is more conveniently done by using one of Ember CLI's generator commands. For instance, let's create a person
model:ember generate model person
app/models/person.js
:import Model from '@ember-data/model';
export default class PersonModel extends Model {
}
store.findRecord()
to retrieve a record by its type and ID. This will return a promise that fulfills with the requested record:// GET /blog-posts/1
this.store.findRecord('blog-post', 1) // => GET /blog-posts/1
.then(function(blogPost) {
// Do something with `blogPost`
});
store.peekRecord()
to retrieve a record by its type and ID, without making a network request. This will return the record only if it is already present in the store:let blogPost = this.store.peekRecord('blog-post', 1); // => no network request
store.findAll()
to retrieve all of the records for a given type:// GET /blog-posts
this.store.findAll('blog-post') // => GET /blog-posts
.then(function(blogPosts) {
// Do something with `blogPosts`
});
store.peekAll()
to retrieve all of the records for a given type that are already loaded into the store, without making a network request:let blogPosts = this.store.peekAll('blog-post'); // => no network request
store.findAll()
returns a PromiseArray
that fulfills to a RecordArray
and store.peekAll
directly returns a RecordArray
.createRecord()
method on the store.store.createRecord('post', {
title: 'Rails is Omakase',
body: 'Lorem ipsum'
});
this.store
.this.store.findRecord('post', 1).then(function(post) {
// ...after the record has loaded
post.title = 'A new post';
});
deleteRecord()
on any instance of Model
. This flags the record as isDeleted
. The deletion can then be persisted using save()
. Alternatively, you can use the destroyRecord
method to delete and persist at the same time.let post = store.peekRecord('post', 1);
post.deleteRecord();
post.isDeleted; // => true
post.save(); // => DELETE to /posts/1
// OR
post = store.peekRecord('post', 2);
post.destroyRecord(); // => DELETE to /posts/2
models
relate to each other.models
, use belongsTo
:app/models/user.js
:import Model, { belongsTo } from '@ember-data/model';
export default class UserModel extends Model {
@belongsTo('profile') profile;
}
app/models/profile.js
:import Model, { belongsTo } from '@ember-data/model';
export default class ProfileModel extends Model {
@belongsTo('user') user;
}
belongsTo
in combination with hasMany
, like this:app/models/blog-post.js
: import Model, { hasMany } from '@ember-data/model';
export default class BlogPostModel extends Model {
@hasMany('comment') comments;
}
app/models/comment.js
:import Model, { belongsTo } from '@ember-data/model';
export default class CommentModel extends Model {
@belongsTo('blog-post') blogPost;
}
hasMany
:app/models/blog-post.js
:import Model, { hasMany } from '@ember-data/model';
export default class BlogPostModel extends Model {
@hasMany('tag') tags;
}
app/models/tag.js
:import Model, { hasMany } from '@ember-data/model';
export default class TagModel extends Model {
@hasMany('blog-post') blogPosts;
}
metadata
. Metadata is data that goes along with a specific model
or type instead of a record.metadata
. Imagine a blog with far more posts than you can display at once. You might query it like so:let result = this.store.query('post', {
limit: 10,
offset: 0
});
metadata
to be returned differently. For example, Ember Data's JSON deserializer looks for a meta key
:{
"post": {
"id": 1,
"title": "Progressive Enhancement is Dead",
"comments": ["1", "2"],
"links": {
"user": "/people/tomdale"
},
// ...
},
"meta": {
"total": 100
}
}
.meta
.store.query()
call :store.query('post').then(result => {
let meta = result.meta;
});
belongsTo
relationship :let post = store.peekRecord('post', 1);
let author = await post.author;
let meta = author.meta;
hasMany
relationship :let post = store.peekRecord('post', 1);
let comments = await post.comments;
let meta = comments.meta;
meta.total
can be used to calculate how many pages of posts you'll have.meta
data outside of the model
hook, you need to return it:app/routes/users.js
:import Route from '@ember/routing/route';
import { service } from '@ember/service';
export default class UsersRoute extends Route {
@service store;
model() {
return this.store.query('user', {}).then((results) => {
return {
users: results,
meta: results.meta
};
});
}
setupController(controller, { users, meta }) {
super.setupController(controller, users);
controller.meta = meta;
}
}
model
works - how it decides what to rerender, and when. This guide covers tracking in more depth, including how it can be used in various types of classes
, and how it interacts with arrays and POJOs.app/components/hello.hbs
:{{this.greeting}}, {{@name}}!
app/components/hello.js
:import Component from '@glimmer/component';
export default class HelloComponent extends Component {
language = 'en';
get greeting() {
switch (this.language) {
case 'en':
return 'Hello';
case 'de':
return 'Hallo';
case 'es':
return 'Hola';
}
}
}
app/templates/application.hbs
<Hello @name="Free Time Learning">
Hello, Free Time Learning!
JavaScript
in ES2015 (also known as ES6). They are defined using the class
keyword, and look like this :class Person {
helloWorld() {
console.log('Hello, world!');
}
}
DI
") design pattern to declare and instantiate classes of objects and dependencies between them.dependency injection
. In most cases, you shouldn't need to learn about how to work with Ember's DI system directly, or how to manually register and setup dependencies. However, there are times when it may be necessary. Ember CLI's initializer
generator:
ember generate initializer shopping-cart
shopping-cart
initializer to inject a cart
property into all the routes in your application:app/initializers/shopping-cart.js
:export function initialize(application) {
application.inject('route', 'cart', 'service:shopping-cart');
};
export default {
initialize
};
Ember CLI's instance-initializer generator
:ember generate instance-initializer logger
app/instance-initializers/logger.js
:export function initialize(applicationInstance) {
let logger = applicationInstance.lookup('logger:main');
logger.log('Hello from the instance initializer!');
}
export default {
initialize
};
run loop
is integrating with a non-Ember API that includes some sort of asynchronous callback. setTimeout
and setInterval
callbackspostMessage
and messageChannel
event handlers<div id="foo"></div>
<div id="bar"></div>
<div id="baz"></div>
foo.style.height = '500px' // write
foo.offsetHeight // read (recalculate style, layout, expensive!)
bar.style.height = '400px' // write
bar.offsetHeight // read (recalculate style, layout, expensive!)
baz.style.height = '200px' // write
baz.offsetHeight // read (recalculate style, layout, expensive!)
composable applications
, they have almost all the same features as normal Ember applications, except an Engine requires a host application to boot it and provide a Router instance. Ember.js
to power sophisticated web applications. These apps may require collaboration among several teams, sometimes distributed around the world. Typically, responsibility is shared by dividing the application into one or more "sections
". How this division is actually implemented varies from team to team.Side effects
: if you change something, it may be unclear how it could affect the rest of platform.Coordination
: when you develop a new feature or make big changes, many teams may need to be in sync to approve it.Complexity
: with a huge dependency tree and many layers of abstraction, developers cannot iterate quickly, and features suffer as a result.Killing Innovation
: a/b testing a cutting-edge feature is hard to do without disrupting the rest of the app and the teams working on it.Slow Onboarding
: new people coming into the team are overwhelmed.@ember/canary-features
package. This package exports a list of all available features and their current status.true
: The feature is present and enabled: the code behind the flag is always enabled in the generated build.null
: The feature is present but disabled in the build output. It must be enabled at runtime.false
: The feature is entirely disabled: the code behind the flag is not present in the generated build.defeatureify
.DS.Model
extends Ember.Object.setupTest
helper.Player
model that has level
and levelName
attributes. We want to call levelUp()
to increment the level
and assign a new levelName
when the player reaches level 5.ember generate model player
.app/models/player.js
:import Model, { attr } from '@ember-data/model';
export default class Player extends Model {
@attr('number', { defaultValue: 0 }) level;
@attr('string', { defaultValue: 'Noob' }) levelName;
levelUp() {
let newLevel = this.level++;
if (newLevel === 5) {
this.levelName = 'Professional';
}
}
}
levelUp
on the player when they are level
4 to assert that the levelName
changes. We will use module
together with the setupTest
helper method :tests/unit/models/player-test.js
:import { module, test } from 'qunit';
import { setupTest } from 'ember-qunit';
import { run } from '@ember/runloop';
module('Unit | Model | player', function(hooks) {
setupTest(hooks);
// Specify the other units that are required for this test.
test('should increment level when told to', function(assert) {
const player = run(() =>
this.owner.lookup('service:store').createRecord('player')
);
// wrap asynchronous call in run loop
run(() => player.levelUp());
assert.equal(player.level, 5, 'level gets incremented');
assert.equal(
player.levelName,
'Professional',
'new level is called professional'
);
});
});​
setupTest
helper which is part of the ember-qunit framework. The tests written for instances like Ember.Controller
are also described as container tests.PostsController
with two properties, a method that sets one of those properties, and an action named setProps
.generate controller posts
.app/controllers/posts.js
:import Controller from '@ember/controller';
import { action } from '@ember/object';
export default class PostsController extends Controller {
propA = 'You need to write tests';
propB = 'And write one for me too';
setPropB(str) {
this.propB = str;
}
@action
setProps(str) {
this.propA = 'Testing is cool';
this.setPropB(str);
}
}
setProps
action directly sets one property, and calls the method to set the other. In our generated test file, Ember CLI already uses the module
and the setupTest
helpers to set up a test container:tests/unit/controllers/posts-test.js
:import { module, test } from 'qunit';
import { setupTest } from 'ember-qunit';
module('Unit | Controller | posts', function(hooks) {
setupTest(hooks);
});
this.owner.lookup
method we get the instance of the PostsController
and can check the action in our test. The this.owner.lookup
helper returns objects generated by the framework in your applications and is also exposed in tests for your usage. Here it will return a singleton instance of the PostsController
.tests/unit/controllers/posts-test.js
:import { module, test } from 'qunit';
import { setupTest } from 'ember-qunit';
module('Unit | Controller | posts', function(hooks) {
setupTest(hooks);
test('should update A and B on setProps action', function(assert) {
assert.expect(4);
// get the controller instance
let controller = this.owner.lookup('controller:posts');
// check the properties before the action is triggered
assert.equal(
controller.propA,
'You need to write tests',
'propA initialized'
);
assert.equal(
controller.propB,
'And write one for me too',
'propB initialized'
);
// trigger the action on the controller by using the `send` method,
// passing in any params that our action may be expecting
controller.send('setProps', 'Testing Rocks!');
// finally we assert that our values have been updated
// by triggering our action.
assert.equal(controller.propA, 'Testing is cool', 'propA updated');
assert.equal(controller.propB, 'Testing Rocks!', 'propB updated');
});
});​