# LaunchDarkly Cloudflare SDK

[![NPM][sdk-cloudflare-npm-badge]][sdk-cloudflare-npm-link]
[![Actions Status][sdk-cloudflare-ci-badge]][sdk-cloudflare-ci]
[![Documentation][sdk-cloudflare-ghp-badge]][sdk-cloudflare-ghp-link]
[![NPM][sdk-cloudflare-dm-badge]][sdk-cloudflare-npm-link]
[![NPM][sdk-cloudflare-dt-badge]][sdk-cloudflare-npm-link]

The LaunchDarkly Cloudflare SDK is designed primarily for use in multi-user Cloudflare workers. It follows the server-side LaunchDarkly model for multi-user contexts. It is not intended for use in desktop and embedded systems applications.

This SDK is a replacement of [launchdarkly-cloudflare-edge-sdk](https://github.com/launchdarkly/cloudflare-edge-sdk). Please consider updating your application to use this package instead.

For more information, see the [complete reference guide for this SDK](https://docs.launchdarkly.com/sdk/server-side/cloudflare).

## Install

```shell
npm i @launchdarkly/cloudflare-server-sdk
```

Then turn on the Node.js compatibility flag in your `wrangler.toml`. This allows the SDK to use `node:events`:

```toml
compatibility_flags = [ "nodejs_compat" ]
```

## Quickstart

Initialize the ldClient with your client side sdk key and the [Cloudflare KV namespace](https://developers.cloudflare.com/workers/runtime-apis/kv#kv-bindings):

```typescript
import { init as initLD } from '@launchdarkly/cloudflare-server-sdk';

export default {
  async fetch(request: Request, env: Bindings): Promise<Response> {
    const sdkKey = 'test-sdk-key';
    const flagKey = 'testFlag1';
    const context = { kind: 'user', key: 'test-user-key-1' };

    // init the ldClient, wait and finally evaluate
    const client = initLD(sdkKey, env.LD_KV);
    await client.waitForInitialization();
    const flagValue = await client.variation(flagKey, context, false);

    return new Response(`${flagKey}: ${flagValue}`);
  },
};
```

See the full [example app](https://github.com/launchdarkly/js-core/tree/main/packages/sdk/cloudflare/example).

## Developing this SDK

```shell
# at js-core repo root
yarn && yarn build && cd packages/sdk/cloudflare

# run tests
yarn test
```

## About LaunchDarkly

- LaunchDarkly is a continuous delivery platform that provides feature flags as a service and allows developers to iterate quickly and safely. We allow you to easily flag your features and manage them from the LaunchDarkly dashboard. With LaunchDarkly, you can:
  - Roll out a new feature to a subset of your users (like a group of users who opt-in to a beta tester group), gathering feedback and bug reports from real-world use cases.
  - Gradually roll out a feature to an increasing percentage of users, and track the effect that the feature has on key metrics (for instance, how likely is a user to complete a purchase if they have feature A versus feature B?).
  - Turn off a feature that you realize is causing performance problems in production, without needing to re-deploy, or even restart the application with a changed configuration file.
  - Grant access to certain features based on user attributes, like payment plan (eg: users on the ‘gold’ plan get access to more features than users in the ‘silver’ plan). Disable parts of your application to facilitate maintenance, without taking everything offline.
- LaunchDarkly provides feature flag SDKs for a wide variety of languages and technologies. Read [our documentation](https://docs.launchdarkly.com/sdk) for a complete list.
- Explore LaunchDarkly
  - [launchdarkly.com](https://www.launchdarkly.com/ 'LaunchDarkly Main Website') for more information
  - [docs.launchdarkly.com](https://docs.launchdarkly.com/ 'LaunchDarkly Documentation') for our documentation and SDK reference guides
  - [apidocs.launchdarkly.com](https://apidocs.launchdarkly.com/ 'LaunchDarkly API Documentation') for our API documentation
  - [blog.launchdarkly.com](https://blog.launchdarkly.com/ 'LaunchDarkly Blog Documentation') for the latest product updates

[sdk-cloudflare-ci-badge]: https://github.com/launchdarkly/js-core/actions/workflows/cloudflare.yml/badge.svg
[sdk-cloudflare-ci]: https://github.com/launchdarkly/js-core/actions/workflows/cloudflare.yml
[sdk-cloudflare-npm-badge]: https://img.shields.io/npm/v/@launchdarkly/cloudflare-server-sdk.svg?style=flat-square
[sdk-cloudflare-npm-link]: https://www.npmjs.com/package/@launchdarkly/cloudflare-server-sdk
[sdk-cloudflare-ghp-badge]: https://img.shields.io/static/v1?label=GitHub+Pages&message=API+reference&color=00add8
[sdk-cloudflare-ghp-link]: https://launchdarkly.github.io/js-core/packages/sdk/cloudflare/docs/
[sdk-cloudflare-dm-badge]: https://img.shields.io/npm/dm/@launchdarkly/cloudflare-server-sdk.svg?style=flat-square
[sdk-cloudflare-dt-badge]: https://img.shields.io/npm/dt/@launchdarkly/cloudflare-server-sdk.svg?style=flat-square