vastec
ember-unused-components
This script searches for unused components in your Ember project. It supports:
- classic structure,
- POD structure,
- Module Unification structure,
{{curly-braces}}syntax,<AngleBrackets>syntax (also nested ones like<Angle::MyBrackets>),ember-light-table's way of definingcellComponent: 'component-name'andcomponent: 'component-name'(component "component-name")helper used in templates- ignoring files,
- whitelisting components unused temporary,
- addons,
- and components being used in addons with
--includeAddonsoption.
It also has a very interesting statistics module.
Installation
$ yarn add -D ember-unused-componentsor
$ npm install ember-unused-components --save-devUsage
Run in your app root directory:
$ ./node_modules/.bin/ember-unused-componentsor
$ npx ember-unused-componentsExpected output (simplified):
No. of components: 277
No. of unused components: 2 (7.22%)
Unused components:
- app/app-tab-panel
- user/user-birthdayIf you feel like there are too many components listed then check Configuration Section.
Stats
Make sure to try optional parameter --stats so you'll see some interesting stuff:
$ npx ember-unused-components --stats
No. of components: 304
No. of unused components: 8 (2.63%)
Unused components:
- report-header
- report-row-title
- reports-settings-dropdown
- ui-checkbox-list
- ui-manage-screen-title
- ui-phone/-body/-message
- ui-table/-cell-currency
- ui-table/-cell-date
The most used component: ui-form-button (101 occurrences)
The number of components used just once: 171 (56.25%)
Usage of {{curly-braces}} vs <AngleBrackets> syntax: 509 (56.81%) vs 387 (43.19%)
Usage of (component "component-name") helper in templates: 70
Usage in JS files (e.g. through `import` or ELT): 63Occurrences
You can also print all occurrences of components that were found. Use --occurrences or --o:
$ npx ember-unused-components --occurrences
// simplified
user-avatar:
> ./app/templates/components/user-card.hbs
- <UserAvatar @src={{_imageSource}} />
welcome-page:
> ./app/templates/application.hbs
- {{welcome-page}}[EXPERIMENTAL] Searching components contained in other packages
You can also print all occurrences of components that were found in included addons. Use --includeAddons to include all found addons, or includeAddons=company-* to only include addons that match company-*
$ npx ember-unused-components --occurrences --includeAddons=company-*
// simplified
[company-buttons] button-a:
> ./app/templates/components/user-card.hbs
- <ButtonA>Button Text</ButtonA>
welcome-page:
> ./app/templates/application.hbs
- {{welcome-page}}Advanced usage
Typically the script should realize if you are using POD structure or not and find its way to components directory.
If you have problems with that, consider:
Forcing POD
To force using POD use --pods argument (alias: -p). Like this:
$ npx ember-unused-components --podsThe script will use the default directory of POD components: app/components. Please let me know if you had to force using POD. I made a simple guessing algorithm that should handle PODs out-of-the-box.
Forcing POD with the custom directory
Your app should be configured to have podModulePrefix property in config/environment.js if you are using POD but if it somehow doesn't work you can specify it through --pods-dir (alias: -pd). Like this:
$ npx ember-unused-components --pods --pods-dir="modules/components-repository"Configuration
In typical use cases, it should work out of the box and you don't have to configure anything but you can consider the following options.
First, you need to create .eucrc.js file in the root directory:
module.exports = {
whitelist: [
'app/app-tab-panel' // we will use it again soon
],
ignore: [
'app/templates/freestyle.hbs' // this is our template with style guides
],
failOnUnused: false // optional, default is false, should we throw errors when we find unused components (useful in CI)
};Whitelist
You can specify which components should not be treated as unused even if the script couldn't find their usage occurrences. This happens when:
- you know that the component will be used in the future and you don't want to remove it and being reminded of that
- you use some kind of "dynamic name resolution" for your components
For the "dynamic name resolution" scenario consider following example. Typical dynamic component look like this:
Template
{{component name car=car}}JavaScript
name: computed('car.type', function () {
return `car-card-${this.get('car.type')}`;
});Result
Which may result in having following components in use:
- car.type = 'suv' =>
{{car-card-suv car=car}} - car.type = 'sport' =>
{{car-card-sport car=car}} - car.type = 'sedan' =>
{{car-card-sedan car=car}}
Unfortunately, this static analysis tool doesn't understand it yet and doesn't know that your component car-card-suv
has been used anywhere.
You can whitelist these components from being marked as unused by referencing to them directly:
module.exports = {
whitelist: [
'car-card-suv',
'car-card-sport',
'car-card-sedan'
]
};or by using wildcard:
module.exports = {
whitelist: ['car-card-*']
};Ignored files
A component might be used in some files like guidelines template (see ember-freestyle) that in fact does not indicate that it is in use. The best practice is to ignore that file:
module.exports = {
ignore: [
'app/templates/freestyle.hbs' // this is our template with style guides
]
};Fail on unused
You might want to throw errors when unused components are found. This is especially useful when running in CI. This behavior is turned off by default.
Turn this behavior on in 2 ways:
Setting the failOnUnused property of your .eucrc.js file to true.
module.exports = {
failOnUnused: true
};
// In practice, it might look something like this:
module.exports = {
failOnUnused: process.env.CI // many CI services like Travis-ci and Circle-ci inject a CI env variable by default.
};Passing the --fail-on-unused flag to the cli:
./node_modules/.bin/ember-unused-components --fail-on-unusedThe .eucrc.js configuration file takes precedence over the cli argument.
Removing components
Auto removing components might be useful but it's not yet supported. Please consider that simple removal of:
template.hbsortemplates/component-name.hbscomponent.jsorcomponents/component-name.jsstyle.cssorstyles/components/style.css
might not remove everything you would like. Examples:
- global CSS classes that are no longer used
- 3rd party JS libraries used only in that component
- translation keys that are no longer needed
- assets (images) that are no longer used
- local overwrites/adjustments for that component made by parent's CSS
So you'll still have some dead code because of unused components.
I encourage you to remove components from the list manually.
Best Practices
Once you delete unused components run the script once again :) You might find that now some other components are no longer used. This happens when the component is used in the unused component.
Example:
{{!-- users-list component --}}
{{#each users as |user|}}
{{user-card user=user}}
{{/each}}So user-card is being used but in unused component users-list. Once you will delete users-list component then user-card
will not be longer used.
Contributing
If you feel like you need some functionality please raise an issue or event better Contribute!
Testing
It's very important to prepare test cases for fixes and new features.
We have a directory test-apps with applications that have different configs and different Ember versions which support or
does not support certain "features" like angle brackets components or module unification project structure.
Running tests
yarn run test
Linting
yarn run lint
Debugging
npx ember-unused-components --debug
License
This project is licensed under the MIT License.