ember-feature-flags  

An ember-cli addon to provide feature flags.

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Tested against ember-source v4.12, v5.8, v5.12, v6.2, canary and beta.

For support for earlier ember-source use ember-feature-flags@6.1.0.

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``
ember install ember-feature-flags
`

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This addon provides a service named features available for injection into your routes, controllers, components, etc.

For example you may check if a feature is enabled:

`js
import Controller from '@ember/controller';
import { inject as service } from '@ember/service';
export default class BillingPlansController extends Controller {
@service features;
get plans() {
if (this.features.isEnabled('newBillingPlans')) {
// Return new plans
} else {
// Return old plans
}
}
}
`

Check whether a feature is enabled in a template by using the feature-flag template helper:

`hbs
// templates/components/homepage-link.hbs
{{#if (feature-flag 'newHomepage')}}
{{link-to "new.homepage"}}
{{else}}
{{link-to "old.homepage"}}
{{/if}}
`

Features can be toggled at runtime, and are bound:

`js
this.features.enable('newHomepage');
this.features.disable('newHomepage');
`

Features can be set in bulk, resetting all existing features:

`js
this.features.setup({
"new-billing-plans": true,
"new-homepage": false
})
`

You may want to set the flags based on the result of a fetch:

`js
// routes/application.js
@service features;
beforeModel() {
return fetch('/my-flag/api').then((data) => {
features.setup(data.json());
});
}
`

NOTE: setup methods reset previously setup flags and their state.

You can get list of known feature flags via flags computed property:
`js
this.features.setup({
"new-billing-plans": true,
"new-homepage": false
});

this.features.flags // ['newBillingPlans', 'newHomepage']
`

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#### config.featureFlags

You can configure a set of initial feature flags in your app's config/environment.js file. This
is an easy way to change settings for a given environment. For example:

`javascript
// config/environment.js
module.exports = function(environment) {
var ENV = {
featureFlags: {
'show-spinners': true,
'download-cats': false
}
};

if (environment === 'production') {
ENV.featureFlags['download-cats'] = true;
}

return ENV;
};
`

#### ENV.LOG_FEATURE_FLAG_MISS

Will log when a feature flag is queried and found to be off, useful to prevent cursing at the app,
wondering why your feature is not working.

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#### enableFeature / disableFeature

Turns on or off a feature for the test in which it is called.
Requires ember-cli-qunit >= 4.1.0 and the newer style of tests that use setupTest, setupRenderingTest, setupApplicationTest.

Example:
`js
import { enableFeature, disableFeature } from 'ember-feature-flags/test-support';

module('Acceptance | Awesome page', function(hooks) {
setupApplicationTest(hooks);

test('it displays the expected welcome message', async function (assert) {
enableFeature('new-welcome-message');

await visit('/');

assert.dom('h1.welcome-message').hasText('Welcome to the new website!');

disableFeature('new-welcome-message');

await settled();

assert.dom('h1.welcome-message').hasText('This is our old website, upgrade coming soon');
});
});
`

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If you use this.features.isEnabled() in components under integration test, you will need to inject a stub service in your tests. Using ember-qunit 0.4.16 or later, here's how to do this:

`js
let featuresService = Service.extend({
isEnabled() {
return false;
}
});

moduleForComponent('my-component', 'Integration | Component | my component', {
integration: true,
beforeEach() {
this.register('service:features', featuresService);
getOwner(this).inject('component', 'features', 'service:features');
}
});
``

Note: for Ember before 2.3.0, you'll need to use ember-getowner-polyfill.

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Contributing

See the Contributing guide for details.

License

This project is licensed under the MIT License.