README
Before you Begin
Harness Feature Flags (FF) is a feature management solution that enables users to change the software’s functionality, without deploying new code. FF uses feature flags to hide code or behaviours without having to ship new versions of the software. A feature flag is like a powerful if statement.
For more information, see https://harness.io/products/feature-flags/
To read more, see https://ngdocs.harness.io/category/vjolt35atg-feature-flags
To sign up, https://app.harness.io/auth/#/signup/
Harness Feature Flags Client SDK for JavaScript
Library for integrating Harness Feature Flags into JavaScript UI applications.
Install
npm i @harnessio/ff-javascript-client-sdk
or
yarn add @harnessio/ff-javascript-client-sdk
Usage
import { initialize, Event } from '@harnessio/ff-javascript-client-sdk'
Initialize SDK with api key and target information.
initialize(FeatureFlagSDKKey: string, target: Target, options?: Options)
In which Target
and Options
are defined as:
interface Target {
identifier: string
name?: string
anonymous?: boolean
attributes?: object
}
interface Options {
baseUrl?: string
debug?: boolean
}
For example:
const cf = initialize('00000000-1111-2222-3333-444444444444', {
identifier: YOUR-TARGET-IDENTIFIER, // Target identifier
name: YOUR-TARGET-NAME, // Optional target name
attributes: { // Optional target attributes
email: 'sample@sample.com'
}
});
cf
instance.
Listening to events from the cf.on(Event.READY, flags => {
// Event happens when connection to server is established
// flags contains all evaluations against SDK key
})
cf.on(Event.CHANGED, flagInfo => {
// Event happens when a changed event is pushed
// flagInfo contains information about the updated feature flag
})
cf.on(Event.DISCONNECTED, () => {
// Event happens when connection is disconnected
})
cf.on(Event.ERROR, error => {
// Event happens when connection some error has occurred
})
Getting value for a particular feature flag
const value = cf.variation('Dark_Theme', false) // second argument is default value when variation does not exist
Cleaning up
Remove a listener of an event by cf.off
.
cf.off(Event.ERROR, error => {
// Do something when an error occurs
})
Remove all listeners:
cf.off()
On closing your application, call cf.close()
to close the event stream.
cf.close();
Import directly from unpkg
In case you want to import this library directly (without having to use npm or yarn):
<script type="module">
import { initialize, Event } from 'https://unpkg.com/@harnessio/ff-javascript-client-sdk@1.4.4/dist/sdk.client.js'
</script>
If you need to support old browsers which don't support ES Module:
<script src="https://unpkg.com/@harnessio/ff-javascript-client-sdk@1.4.4/dist/sdk.client.js"></script>
<script>
var initialize = HarnessFFSDK.initialize
var Event = HarnessFFSDK.Event
</script>
Remember to change the version 1.4.4
in the unpkg url accordingly.
License
Apache version 2.