flipper-js

Flipper-js

Flipper-js manage the feature flipping in your application

Inspired from the GEM Flipper Ruby GEM Flipper

Features

• CLI management
• In code management
• UI management

Installation

npm i flipper-js

Configuration

The configuration is on a json file (features.json) that you have to create on your application :

{
  "features": {
    "feature1": true,
    "feature2": false
  },
  "storage": {
    "type": "local"
  }
}

Storage types are

• local : use this file (read and write) to manage the feature flipping.
• redis : use the redis (you provide) to store the feature.

Env vars

• FLIPPER_API_KEY : the api key used to authenticate interaction with the flipper UI
• FLIPPER_REDIS_URL : The redis connection url

CLI

The feature flipping could be managed by a CLI

npx flipper-js --help

you have to set the env var FLIPPER_REDIS_URL if you are using the redis storage type.

export FLIPPER_REDIS_URL=redis://user:passxord@redis:6379

Options

-V, --version output the version number -h, --help display help for command

Commands

• list : List all features and their statuses
• enable "feature" : Enable a feature
• disable "feature" : Disable a feature
• add "feature" : Add a new feature (enabled by default)

In code management

Initialisation

import  path  from  'path'
import { Flipper } from  'flipper-js'

// Init flipper with json config path (optional)
Flipper.init(path.join(__dirname, '../features.json'))

Usage

import { Flipper } from  'flipper-js'

// Check if a feature is enabled
await Flipper.isEnabled('feature1')

// Enabled a feature
await Flipper.enable('feature1')

// Disabled a feature
await Flipper.disable('feature1')

// List all features
await Flipper.list()

UI management

UI management is using an express router

The router is exported and could be included in your app.

Example with Express

import { Flipper, User, FlipperRouter } from  'flipper-js'

Flipper.init()

// Expose /flipper-js on your application
app.use(FlipperRouter.of('express'))

User.addUser(process.env.FLIPPER_USER_LOGIN, process.env.FLIPPER_USER_PASSWORD)
// You can add several users

Other router (Nest.js, Fastify) are coming

To access : launch https://yourserver.com/flipper-js

The connection is the login provided by the addUser method.

Inside the UI, you can simply enable or disabled features.