Routes and Templates
To demonstrate the basic setup and processing of an Ember application, this section will walk through building an Ember application for a property rental site called Super Rentals. It will start with a homepage, an about page and a contact page. Let's take a look at the application from the user perspective before we get started.
We arrive at the home page which shows a list of rentals. From here, we will be able to navigate to an about page and a contact page.
Now, let's start by building our "about" page.
Remember, when the URL path /about is loaded,
the router will map the URL to the route handler of the same name, about.js.
The route handler then loads a template.
An About Route
If we run ember help generate, we can see a variety of tools that come with Ember for automatically generating files for various Ember resources.
Let's use the route generator to start our about route.
ember generate route about
or for short,
ember g route about
We can then see what actions were taken by the generator:
installing route
create app/routes/about.js
create app/templates/about.hbs
updating router
add route about
installing route-test
create tests/unit/routes/about-test.js
Three new files are created: one for the route handler, one for the template the route handler will render, and a test file. The fourth file that is touched is the router.
When we open the router, we can see that the generator has mapped a new about route for us.
This route will load the about route handler.
import Ember from 'ember';
import config from './config/environment';
const Router = Ember.Router.extend({
location: config.locationType,
rootURL: config.rootURL
});
Router.map(function() {
this.route('about');
});
export default Router;
By default, the about route handler loads the about.hbs template.
This means we don't actually have to change anything in the new app/routes/about.js file for the about.hbs template to render as we want.
With all of the routing in place from the generator, we can get right to work on coding our template.
For our about page, we'll add some HTML that has a bit of information about the site:
Run ember serve (or ember s for short) from the shell to start the Ember development server,
and then go to http://localhost:4200/about to see our new app in action!
A Contact Route
Let's create another route with details for contacting the company. Once again, we'll start by generating a route, a route handler, and a template.
ember g route contact
We see that our generator has created a contact route in the app/router.js file,
and a corresponding route handler in app/routes/contact.js.
Since we will be using the contact template, the contact route does not need any additional changes.
In contact.hbs, we can add the details for contacting our Super Rentals HQ:
Now we have completed our second route.
If we go to the URL http://localhost:4200/contact, we'll arrive on our contact page.
Navigating with Links and the {{link-to}} Helper
We really don't want users to have to know our URLs in order to move around our site, so let's add some navigational links at the bottom of each page. Let's make a contact link on the about page and an about link on the contact page.
Ember has built-in helpers that provide functionality such as linking to other routes.
Here we will use the {{link-to}} helper in our code to link between routes:
The {{link-to}} helper takes an argument with the name of the route to link to, in this case: contact.
When we look at our about page at http://localhost:4200/about, we now have a working link to our contact page.
Now, we'll add a link to our contact page so we can navigate back and forth between about and contact.
A Rentals Route
We want our application to show a list of rentals that users can browse.
To make this happen we'll add a third route and call it rentals.
ember g route rentals
Let's update the newly generated rentals.hbs with some basic markup to seed our rentals list page.
We'll come back to this page later to add in the actual rental properties.
An Index Route
With our two static pages in place, we are ready to add our home page which welcomes users to the site.
At this point our main page in our application is our rentals page, for which we've already created a route.
So we want our index route to simply forward to the rentals route we've already created.
Using the same process we did for our about and contact pages, we will first generate a new route called index.
ember g route index
We can see the now familiar output for the route generator:
installing route
create app/routes/index.js
create app/templates/index.hbs
installing route-test
create tests/unit/routes/index-test.js
Unlike the other route handlers we've made so far, the index route is special:
it does NOT require an entry in the router's mapping.
We'll learn more about why the entry isn't required when we look at nested routes in Ember.
We can start by implementing the unit test for index.
Since all we want to do is transition to rentals, our unit test will make sure that the route's replaceWith method is called with the desired route.
replaceWith is similar to the route's transitionTo function, the difference being that replaceWith will replace the current URL in the browser's history, while transitionTo will add to the history.
Since we want our rentals route to serve as our home page, we will use the replaceWith function.
We'll verify that by stubbing the replaceWith method for the route and asserting that the rentals route is passed when called.
import { moduleFor, test } from 'ember-qunit';
moduleFor('route:index', 'Unit | Route | index');
test('should transition to rentals route', function(assert) {
let route = this.subject({
replaceWith(routeName) {
assert.equal(routeName, 'rentals', 'replace with route name rentals');
}
});
route.beforeModel();
});
In our index route, we simply add the replaceWith invocation.
import Ember from 'ember';
export default Ember.Route.extend({
beforeModel() {
this._super(...arguments);
this.replaceWith('rentals');
}
});
Now visiting the root route / will result in the /rentals URL loading.
Adding a Banner with Navigation
In addition to providing button-style links in each route of our application, we would like to provide a common banner to display both the title of our application, as well as its main pages.
First, create the application template by typing ember g template application.
installing template
create app/templates/application.hbs
When application.hbs exists, anything you put in it is shown for every page in the application. Now add the following banner navigation markup:
Notice the inclusion of an {{outlet}} within the body div element. The {{outlet}} defers to the router, which will render in its place the markup for the current route, meaning the different routes we develop for our application will get rendered there.
Now that we've added routes and linkages between them, the three acceptance tests we created for navigating to our routes will now pass.
