ld-react

The quickest and easiest way to integrate launch darkly with react 🎉

Why this package?

• Easy and fast to use. Two steps to get feature flags into your react app.
• Uses hooks and context api under the hood. No redux required.
• Supports subscription out of the box. You get live changes on the client as you toggle features.
• You automatically get camelCased keys as opposed to the default kebab-cased.

Installation

yarn add ld-react@next

Quickstart

1. Call useLaunchDarkly hook with your App:

   import {useLaunchDarkly} from 'ld-react';
   
   const App = () =>
     <div>
       <Home />
    </div>;
   
   export default () => useLaunchDarkly(App, {clientSideId: 'your-client-side-id'});

2. useFlags in your component to get flags:

   import {useFlags} from 'ld-react';
   
   const Home = () => {
      const {devTestFlag} = useFlags();
      return devTestFlag ? <div>Flag on</div> : <div>Flag off</div>;
   };
   
   export default Home;

That's it!

API

useLaunchDarkly(Component, {clientSideId, user, options})

This is a custom hook which accepts a component and a config object with the above properties. Component and clientSideId are mandatory.

For example:

import {useLaunchDarkly} from 'ld-react';

const App = () =>
  <div>
    <Home />
 </div>;

// GOTCHA: export a function because hooks can only be used inside function components
export default () => useLaunchDarkly(App, {clientSideId: 'your-client-side-id'});

The user property is optional. You can initialise the sdk with a custom user by specifying one. This must be an object containing at least a "key" property. If you don't specify a user object, ld-react will create a default one that looks like this:

const defaultUser = {
  key: uuid.v4(), // random guid
  ip: ip.address(),
  custom: {
    browser: userAgentParser.getResult().browser.name,
    device
  }
};

For more info on the user object, see here.

The options property is optional. It can be used to pass in extra options such as Bootstrapping. For example:

useLaunchDarkly(Component, {
    clientSideId,
    options: {
      bootstrap: 'localStorage',
    },
});

useFlags()

This is a custom hook which returns an object containing all your flags. Your flags will be available as camelCased properties. For example:

import {useFlags} from 'ld-react';

const Home = () => {
   const {devTestFlag} = useFlags();
   return devTestFlag ? <div>Flag on</div> : <div>Flag off</div>;
};

export default Home;

ldClient

Internally the ld-react initialises the ldclient-js sdk and stores a reference to the resultant ldClient object in memory. You can use this object to access the official sdk methods directly. For example, you can do things like:

import {ldClient} from 'ld-react';

class Home extends Component {
 
  // track goals
  onAddToCard = () => ldClient.track('add to cart'); 
 
  // change user context
  onLoginSuccessful = () => ldClient.identify({key: 'someUserId'});
  
  // ... other implementation
}

For more info on changing user context, see the official documentation.

Example

Check the example for a fully working spa with react and react-router. Remember to enter your own client side sdk in useLaunchDarkly hook and create a test flag called dev-test-flag before running the example!