This guide will teach you how to build a simple app using Ember from scratch.
We'll cover these steps:
- Installing Ember.
- Creating a new application.
- Defining a route.
- Writing a UI component.
- Building your app to be deployed to production.
Install Ember
You can install Ember with a single command using npm, the Node.js package manager. Type this into your terminal:
npm install -g ember-cli
Don't have npm? Learn how to install Node.js and npm here. For a full list of dependencies necessary for an Ember CLI project, visit the Ember CLI Guides - Installing.
Create a New Application
Once you've installed 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
This one command will create a new directory called ember-quickstart
and set up a new Ember application inside of it.
Out of the box, your application will include:
- A development server.
- Template compilation.
- JavaScript and CSS minification.
- Modern features via Babel.
By providing everything you need to build production-ready web applications in an integrated package, Ember makes starting new projects a breeze.
Let's make sure everything is working properly.
cd
into the application directory ember-quickstart
and start the development server by typing:
cd ember-quickstart
ember serve
After a few seconds, you should see output that looks like this:
Livereload server on http://localhost:7020
Serving on http://localhost:4200/
(To stop the server at any time, type Ctrl-C in your terminal.)
Open http://localhost:4200
in your browser of choice.
You should see an Ember welcome page and not much else.
Congratulations! You just created and booted your first Ember app.
We will start by editing the application
template.
This template is always on screen while the user has your application loaded.
In your editor, open app/templates/application.hbs
and change it to the following:
Ember detects the changed file and automatically reloads the page for you in the background.
You should see that the welcome page has been replaced by "PeopleTracker".
You also added an {{outlet}}
to this page,
which means that any route will be rendered in that place.
Define a Route
Let's build an application that shows a list of scientists. To do that, the first step is to create a route. For now, you can think of routes as being the different pages that make up your application.
Ember comes with generators that automate the boilerplate code for common tasks.
To generate a route, type this in a new terminal window in your ember-quickstart
directory:
ember generate route scientists
You'll see output like this:
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
That is Ember telling you that it has created:
- A template to be displayed when the user visits
/scientists
. - A
Route
object that fetches the model used by that template. - An entry in the application's router (located in
app/router.js
). - A unit test for this route.
Open the newly-created template in app/templates/scientists.hbs
and add the following HTML:
In your browser, open 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.
Now that we've got the scientists
template rendering,
let's give it some data to render.
We do that by specifying a model for that route,
and we can specify a model by editing app/routes/scientists.js
.
We'll take the code created for us by the generator and add a 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'];
}
}
This code example uses a feature of JavaScript called classes. Learn more with this overview of the latest JavaScript features.
In a route's 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.
Now let's tell Ember how to turn that array of strings into HTML.
Open the scientists
template and add the following code to loop through the array and print it:
Here, we use the each
helper to loop over 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.
The end result is that there will be one <li>
element corresponding to each
scientist in the array inside the <ul>
unordered list.
Create a UI Component
As your application grows, you will notice you are sharing UI elements between multiple pages, or using them multiple times on the same page. Ember makes it easy to refactor your templates into reusable components.
Let's create a <PeopleList>
component that we can use in multiple places to show a list of people.
As usual, there's a generator that makes this easy for us. Make a new component by typing:
ember generate component people-list
Copy and paste the scientists
template into the <PeopleList>
component's template and edit it to look as follows:
Note that we've changed the title from a hard-coded string ("List of Scientists")
to {{@title}}
. The @
indicates that @title
is an argument that will be
passed into the component, which makes it easier to reuse the same component in
other parts of the app we are building.
We've also renamed scientist
to the more-generic person
,
decreasing the coupling of our component to where it's used.
Our component is called <PeopleList>
, based on its name on the file system. Please note that the letters P and L are capitalized.
Save this template and switch back to the scientists
template.
We're going to tell our component:
- What title to use, via the
@title
argument. - What array of people to use, via the
@people
argument. We'll provide this route's@model
as the list of people.
We'll need to make some changes to the code we wrote before.
In the rest of the code examples in this tutorial, whenever we add or remove code, we will show a "diff." The lines you need to remove have a minus sign in front of them, and the lines you should add have a plus sign. If you are using a screen reader while you go through the Guides, we recommend using Firefox and NVDA or Safari and VoiceOver for the best experience.
Let's replace all our old code with our new componentized version:
Go back to your browser and you should see that the UI looks identical. The only difference is that now we've componentized our list into a version that's more reusable and more maintainable.
You can see this in action if you create a new route that shows a different list of people.
As an additional exercise (that we won't cover),
you can try to create a programmers
route that shows a list of famous programmers.
If you re-use the <PeopleList>
component, you can do it with almost no code at all.
Responding to user interactions
So far, our application is listing data, but there is no way for the user to interact with the information. In web applications we often want to respond to user actions like clicks or hovers. Ember makes this easy to do.
First, we can modify the <PeopleList>
component to include a button:
Now that we have a button, we need to wire it up to do something when a user
clicks on it. For simplicity, let's say we want to show an alert
dialog with
the person's name when the button is clicked.
So far, our <PeopleList>
component is purely presentational – it takes some
inputs as arguments and renders them using a template. To introduce behavior
to our component – handling the button click in this case, we will need to
attach some code to the component.
In addition to the template, a component can also have a JavaScript file for
this exact purpose. Go ahead and create a .js
file with the same name and in
the same directory as our template (app/components/people-list.js
),
and paste in the following content:
import Component from '@glimmer/component';
import { action } from '@ember/object';
export default class PeopleListComponent extends Component {
@action
showPerson(person) {
alert(`The person's name is ${person}!`);
}
}
Note: If you want this file created for you, you may pass the -gc
flag when running the component generator.
Here, we created a basic component class and added a method that accepts a
person as an argument and brings up an alert dialog with their name. The
@action
decorator indicates we want to use this method as an action
in our template, in response to user interaction.
Now that we have implemented the desired behavior, we can go back to the component's template and wire everything up:
Here, we used the on
modifier to attach the this.showPerson
action to
the button in the template.
There is a problem with this though – if you tried this in the browser, you
will quickly discovered that clicking on the buttons will bring up an alert
dialog that said "The person's name is [Object Mousevent]
!" – eek!
The cause of this bug is that we wrote our action to take an argument – the person's name – and we forgot to pass it. The fix is easy enough:
Instead of passing the action to the on
modifier directly, we used the fn
helper to pass the person
as an argument which our action expects.
Feel free to try this in the browser. Finally, everything should behave exactly as we hoped!
Building For Production
Now that we've written our application and verified that it works in development, it's time to get it ready to deploy to our users.
To do so, run the following command:
ember build --environment=production
The build
command packages up all of the assets that make up your
application—JavaScript, templates, CSS, web fonts, images, and
more.
In this case, we told Ember to build for the production environment via the --environment
flag.
This creates an optimized bundle that's ready to upload to your web host.
Once the build finishes,
you'll find all of the concatenated and minified assets in your application's dist/
directory.
The Ember community values collaboration and building common tools that everyone relies on. If you're interested in deploying your app to production in a fast and reliable way, check out the Ember CLI Deploy addon.
If you deploy your application to an Apache web server, first create a new virtual host for the application.
To make sure all routes are handled by index.html
,
add the following directive to the application's virtual host configuration:
FallbackResource index.html