Flipt is an open source developer friendly feature flagging solution, that allows for easy management and fast feature evaluation.

This provider is an implementation on top of the official Flipt Browser Client Side SDK.

The main difference between this provider and @openfeature/flipt-provider is that it uses a static evaluation context.
This provider is more sustainable for client-side implementation.

If you want to know more about this pattern, we encourage you to read this blog post.

npm install @openfeature/web-sdk @openfeature/flipt-web-provider

To initialize the OpenFeature client with Flipt, you can use the following code snippet:

import { FliptWebProvider } from '@openfeature/flipt-web';

const provider = new FliptWebProvider('namespace-of-choice', { url: 'http://your.upstream.flipt.host' });
await OpenFeature.setProviderAndWait(provider);

After the provider gets initialized, you can start evaluations of feature flags like so:

const evaluationCtx: EvaluationContext = {
  targetingKey: 'myentity',
  email: 'john@flipt.io',
};

// Set the static context for OpenFeature
await OpenFeature.setContext(evaluationCtx);

// Attach the provider to OpenFeature
const client = await OpenFeature.getClient();

// You can now use the client to evaluate your flags
const details = client.getStringDetails('my-feature', 'default');

You can pass the following options to the FliptWebProvider constructor:

OpenFeature standardizes the evaluation context to include a targetingKey, and some other additional arbitrary properties that each provider can use fit for their use case.

For Flipt, we translate the targetingKey as the entityId, and the rest of the OpenFeature evaluation context as the context in Flipt vernacular. You can find the meaning of those two words here in our API docs.

For example, an OpenFeature Evaluation context that has this structure:

{
  "targetingKey": "my-targeting-id",
  "email": "john@flipt.io",
  "userId": "this-very-long-user-id"
}

will get transformed to the following for Flipt:

{
  "entityId": "my-targeting-id",
  "context": {
    "email": "john@flipt.io",
    "userId": "this-very-long-user-id"
  }
}

Run nx package providers-flipt-web to build the library.

Run nx test providers-flipt-web to execute the unit tests via Jest.