@harnessio/ff-javascript-client-sdk

Harness Feature Flags Client SDK for JavaScript

Library for integrating Harness Feature Flags into JavaScript 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: '[e-mail]'
    }
  }, {
    baseURL: HARNESS-FEATURE-FLAG-BASE-URL,  // Optional Harness Feature Flag server base URL
  });

Listening to events from the cf instance.

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, () => {
  // 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, () => {
  // 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();

License

Apache version 2.