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Managing Dependencies


As you're developing your Ember app, you are likely to run into common scenarios that aren't addressed by Ember itself. Perhaps you want to use a CSS preprocessor to write your stylesheets, or you want to use a popular JS library, or maybe you want to import components written by a different department within your organization.

Ember CLI provides a common format called Ember Addons for distributing reusable libraries to solve some of these problems. Additionally, you may want to make use of front-end dependencies like a CSS framework or a JavaScript datepicker that aren't specific to Ember apps.

Addons

Addons are JavaScript packages that integrate with Ember. For example, ember-cli-sass is an addon that allows you to use SASS/SCSS in your applications. You can install it using the Ember CLI with the following command:

ember install ember-cli-sass

This will modify your package.json (and package-lock.json), typically bringing in other dependencies. Some addons will also add additional files to your projects when relevant.

There are many addons that cover all kinds of use cases. For more detail, as well as examples of what addons can do, we invite you to have a look at the Ember CLI documentation.

The Ember community publishes and maintains many addons, and it can be difficult to know if one (or many!) exists that covers your needs. The website Ember Observer keeps an up-to-date index of Ember Addons, sorted by categories, and rated according to objective metrics. If you are looking for an addon, we recommend that you start there!

Regular npm packages

While dependencies can be managed in several ways, it's worth noting that the process can be greatly simplified for new developers by using ember-auto-import, which offers zero config imports from npm packages. It's easily installed using ember install ember-auto-import. For further usage instructions, please follow the project README.

Other assets

Third-party JavaScript not available as an addon or npm package should be placed in the vendor/ folder in your project.

Your own assets (such as robots.txt, favicon, custom fonts, etc) should be placed in the public/ folder in your project.

Compiling Assets

When you're using dependencies that are not included in an addon, you will have to instruct Ember CLI to include your assets in the build. This is done using the asset manifest file ember-cli-build.js. You should only try to import assets located in the node_modules and vendor folders. bower_components also still works, but is recommended against, unless you have no other choice. Even bower recommends not to use itself anymore.

Globals provided by JavaScript assets

The globals provided by some assets (like moment in the below example) can be used in your application without the need to import them. Provide the asset path as the first and only argument.

app.import('node_modules/moment/moment.js');

You will need to add "moment" to the globals section in .eslintrc.js to prevent ESLint errors about using an undefined variable.

Anonymous AMD JavaScript modules

You can transform an anonymous AMD module to a named one by using the amd transformation.

app.import('node_modules/moment/moment.js', {
  using: [
    { transformation: 'amd', as: 'moment' }
  ]
});

This transformation allows you to import moment in your app. (e.g. import moment from 'moment';)

CommonJS JavaScript modules

ember-cli-cjs-transform allows us to import CommonJS modules into our Ember app. It also does auto-rollup and some nice caching, so it should pull in all the deps that are pulled in with require for you automatically. It is not yet included with Ember CLI by default, so you will need to install it.

ember install ember-cli-cjs-transform
app.import('node_modules/showdown/dist/showdown.js', {
  using: [
    { transformation: 'cjs', as: 'showdown' }
  ]
});

You can now import them in your app. (e.g. import showdown from 'showdown';)

Environment-Specific Assets

If you need to use different assets in different environments, specify an object as the first parameter. That object's key should be the environment name, and the value should be the asset to use in that environment.

app.import({
  development: 'node_modules/moment/moment.js',
  production:  'node_modules/moment/min/moment.min.js'
});

If you need to import an asset in only one environment you can wrap app.import in an if statement. For assets needed during testing, you should also use the {type: 'test'} option to make sure they are available in test mode.

if (app.env === 'development') {
  // Only import when in development mode
  app.import('vendor/ember-renderspeed/ember-renderspeed.js');
}
if (app.env === 'test') {
  // Only import in test mode and place in test-support.js
  app.import('node_modules/sinonjs/sinon.js', { type: 'test' });
  app.import('node_modules/sinon-qunit/lib/sinon-qunit.js', { type: 'test' });
}

CSS

Provide the asset path as the first argument:

app.import('node_modules/foundation/css/foundation.css');

All style assets added this way will be concatenated and output as /assets/vendor-35ee856956b3c5e3e5fd3d6d5a90427b.css.

Other Assets

All assets located in the public/ folder will be copied as is to the final output directory, dist/.

For example, a favicon located at public/images/favicon.ico will be copied to dist/images/favicon.ico.

All third-party assets, included either manually in vendor/ or via a package manager like npm, must be added via import().

Third-party assets that are not added via import() will not be present in the final build.

By default, imported assets will be copied to dist/ as they are, with the existing directory structure maintained.

app.import('node_modules/font-awesome/fonts/fontawesome-webfont.ttf');

This example would create the font file in dist/font-awesome/fonts/fontawesome-webfont.ttf.

You can also optionally tell import() to place the file at a different path. The following example will copy the file to dist/assets/fontawesome-webfont.ttf.

app.import('node_modules/font-awesome/fonts/fontawesome-webfont.ttf', {
  destDir: 'assets'
});

If you need to load certain dependencies before others, you can set the prepend property equal to true on the second argument of import(). This will prepend the dependency to the vendor file instead of appending it, which is the default behavior.

app.import('node_modules/es5-shim/es5-shim.js', {
  type: 'vendor',
  prepend: true
});