@flipt-io/flipt

Flipt Node Library

Documentation

API documentation is available at https://www.flipt.io/docs/reference/overview.

Breaking Changes

Version 0.2.2 of this client introduced a breaking change as it requires the passing of namespace parameter to all methods that require it. This is to support the new namespace functionality added to Flipt v1.20.0.

:warning: If you are running an older version of Flipt server (< v1.20.0), you should use a pre 0.2.2 version of this client.

Install

npm i @flipt-io/flipt@{version}

Usage

import { FliptApiClient } from '@flipt-io/flipt';

const client = new FliptApiClient({
  environment: "http://localhost:8080",
  auth: {
    credentials: {
      username: "YOUR_USERNAME",
      password: "YOUR_PASSWORD",
    },
  },
});

Evaluation

In v1.24.0 of Flipt server, we added a new set of Evaluation API endpoints to allow evaluating of both boolean and multivariate flags. This SDK supports both sets of evaluation APIs (old and new) as of v0.2.7.

The previous API endpoints at /api/v1/evaluate have been deprecated and may be removed in a future release. We recommend using the new Evaluation API at /evaluate/v1/ for all new projects.

For more information on the new Evaluation API, please see the API documentation or blog post on Flipt v1.24.0.

const response = await client.evaluation.variant({
  namespaceKey: DEFAULT_NAMESPACE,
  flagKey: "abc123",
  entityId: uuidv4(),
  context: {},
});

console.log("Received response from Flipt!", response);

Type Safe Flags

If you are using TypeScript, you can use our new flipt-io/typed CLI to generate Flag and Context definitions from flag state which will allow you to get type safety on your flags and their values.

// Generated by @flipt-io/typed
export type Flag = {
  key: "maintenance-mode";
  value?: "on" | "off";
};

Check out the flipt-io/typed repository and our blog post for more information.

Metrics

There is support for Datadog RUM through this client. This allows you to track the values of feature flag evaluation and how it relates to active browser sessions.

To start tracking feature flags on Datadog:

import { datadogRum } from '@datadog/browser-rum';
import { FliptMetrics } from '@flipt-io/flipt/metrics';

datadogRum.init({
  applicationId: '<APPLICATION_ID>',
  clientToken: '<CLIENT_TOKEN>',
  site: 'datadoghq.com',
  service:'<SERVICE_NAME>',
  env:'<ENV_NAME>',
  enableExperimentalFeatures: ["feature_flags"],
  sessionSampleRate:100,
  sessionReplaySampleRate: 20,
  trackUserInteractions: true,
  trackResources: true,
  trackLongTasks: true,
  defaultPrivacyLevel:'mask-user-input'
});
  
datadogRum.startSessionReplayRecording();

const metricsClient = new FliptMetrics(new FliptApiClient({
  environment: "http://localhost:8080",
  auth: {
    credentials: {
      username: "YOUR_USERNAME",
      password: "YOUR_PASSWORD",
    },
  },
}).evaluation, datadogRum);

const response = await metricsClient.variant({
  namespaceKey: "default",
  flagKey: "hello-this",
  entityId: uuidv4(),
  context: {},
});

Contributing

While we value open-source contributions to this SDK, this library is generated programmatically. Additions made directly to this library would have to be moved over to our generation code, otherwise they would be overwritten upon the next generated release. Feel free to open a PR as a proof of concept, but know that we will not be able to merge it as-is. We suggest opening an issue first to discuss with us!

On the other hand, contributions to the README are always very welcome!