|
7 | 7 | </picture> |
8 | 8 | </p> |
9 | 9 |
|
10 | | -<h2 align="center">This package has been deprecated. It's been renamed (moved without changes) to @openfeature/server-sdk.</h2> |
| 10 | +<h2 align="center">OpenFeature Node.js SDK</h2> |
| 11 | + |
| 12 | +<!-- x-hide-in-docs-end --> |
| 13 | +<!-- The 'github-badges' class is used in the docs --> |
| 14 | +<p align="center" class="github-badges"> |
| 15 | + <a href="https://github.com/open-feature/spec/tree/v0.7.0"> |
| 16 | + <img alt="Specification" src="https://img.shields.io/static/v1?label=specification&message=v0.7.0&color=yellow&style=for-the-badge" /> |
| 17 | + </a> |
| 18 | + <!-- x-release-please-start-version --> |
| 19 | + <a href="https://github.com/open-feature/js-sdk/releases/tag/js-sdk-v1.6.1"> |
| 20 | + <img alt="Release" src="https://img.shields.io/static/v1?label=release&message=v1.6.1&color=blue&style=for-the-badge" /> |
| 21 | + </a> |
| 22 | + <!-- x-release-please-end --> |
| 23 | + <br/> |
| 24 | + <a href="https://open-feature.github.io/js-sdk/modules/OpenFeature_JS_SDK.html"> |
| 25 | + <img alt="API Reference" src="https://img.shields.io/badge/reference-teal?logo=javascript&logoColor=white" /> |
| 26 | + </a> |
| 27 | + <a href="https://www.npmjs.com/package/@openfeature/js-sdk"> |
| 28 | + <img alt="NPM Download" src="https://img.shields.io/npm/dm/%40openfeature%2Fjs-sdk" /> |
| 29 | + </a> |
| 30 | + <a href="https://codecov.io/gh/open-feature/js-sdk"> |
| 31 | + <img alt="codecov" src="https://codecov.io/gh/open-feature/js-sdk/branch/main/graph/badge.svg?token=3DC5XOEHMY" /> |
| 32 | + </a> |
| 33 | + <a href="https://bestpractices.coreinfrastructure.org/projects/6594"> |
| 34 | + <img alt="CII Best Practices" src="https://bestpractices.coreinfrastructure.org/projects/6594/badge" /> |
| 35 | + </a> |
| 36 | +</p> |
| 37 | +<!-- x-hide-in-docs-start --> |
| 38 | + |
| 39 | +[OpenFeature](https://openfeature.dev) is an open standard that provides a vendor-agnostic, community-driven API for feature flagging that works with your favorite feature flag management tool. |
| 40 | + |
| 41 | +<!-- x-hide-in-docs-end --> |
| 42 | + |
| 43 | +## 🚀 Quick start |
| 44 | + |
| 45 | +### Requirements |
| 46 | + |
| 47 | +- Node.js version 16+ |
| 48 | + |
| 49 | +### Install |
| 50 | + |
| 51 | +#### npm |
| 52 | + |
| 53 | +```sh |
| 54 | +npm install --save @openfeature/js-sdk |
| 55 | +``` |
| 56 | + |
| 57 | +#### yarn |
| 58 | + |
| 59 | +```sh |
| 60 | +yarn add @openfeature/js-sdk |
| 61 | +``` |
| 62 | + |
| 63 | +### Usage |
| 64 | + |
| 65 | +```ts |
| 66 | +import { OpenFeature } from '@openfeature/js-sdk'; |
| 67 | + |
| 68 | +// Register your feature flag provider |
| 69 | +OpenFeature.setProvider(new YourProviderOfChoice()); |
| 70 | + |
| 71 | +// create a new client |
| 72 | +const client = OpenFeature.getClient(); |
| 73 | + |
| 74 | +// Evaluate your feature flag |
| 75 | +const v2Enabled = await client.getBooleanValue('v2_enabled', false); |
| 76 | + |
| 77 | +if (v2Enabled) { |
| 78 | + console.log("v2 is enabled"); |
| 79 | +} |
| 80 | +``` |
| 81 | + |
| 82 | +### API Reference |
| 83 | + |
| 84 | +See [here](https://open-feature.github.io/js-sdk/modules/OpenFeature_JS_SDK.html) for the complete API documentation. |
| 85 | + |
| 86 | +## 🌟 Features |
| 87 | + |
| 88 | +| Status | Features | Description | |
| 89 | +| ------ | ------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------- | |
| 90 | +| ✅ | [Providers](#providers) | Integrate with a commercial, open source, or in-house feature management tool. | |
| 91 | +| ✅ | [Targeting](#targeting) | Contextually-aware flag evaluation using [evaluation context](https://openfeature.dev/docs/reference/concepts/evaluation-context). | |
| 92 | +| ✅ | [Hooks](#hooks) | Add functionality to various stages of the flag evaluation life-cycle. | |
| 93 | +| ✅ | [Logging](#logging) | Integrate with popular logging packages. | |
| 94 | +| ✅ | [Named clients](#named-clients) | Utilize multiple providers in a single application. | |
| 95 | +| ✅ | [Eventing](#eventing) | React to state changes in the provider or flag management system. | |
| 96 | +| ✅ | [Shutdown](#shutdown) | Gracefully clean up a provider during application shutdown. | |
| 97 | +| ✅ | [Extending](#extending) | Extend OpenFeature with custom providers and hooks. | |
| 98 | + |
| 99 | +<sub>Implemented: ✅ | In-progress: ⚠️ | Not implemented yet: ❌</sub> |
| 100 | + |
| 101 | +### Providers |
| 102 | + |
| 103 | +[Providers](https://openfeature.dev/docs/reference/concepts/provider) are an abstraction between a flag management system and the OpenFeature SDK. |
| 104 | +Look [here](https://openfeature.dev/ecosystem/?instant_search%5BrefinementList%5D%5Btype%5D%5B0%5D=Provider&instant_search%5BrefinementList%5D%5Bcategory%5D%5B0%5D=Server-side&instant_search%5BrefinementList%5D%5Btechnology%5D%5B0%5D=JavaScript) for a complete list of available providers. |
| 105 | +If the provider you're looking for hasn't been created yet, see the [develop a provider](#develop-a-provider) section to learn how to build it yourself. |
| 106 | + |
| 107 | +Once you've added a provider as a dependency, it can be registered with OpenFeature like this: |
| 108 | + |
| 109 | +```ts |
| 110 | +OpenFeature.setProvider(new MyProvider()) |
| 111 | +``` |
| 112 | + |
| 113 | +In some situations, it may be beneficial to register multiple providers in the same application. |
| 114 | +This is possible using [named clients](#named-clients), which is covered in more details below. |
| 115 | + |
| 116 | +### Targeting |
| 117 | + |
| 118 | +Sometimes, the value of a flag must consider some dynamic criteria about the application or user, such as the user's location, IP, email address, or the server's location. |
| 119 | +In OpenFeature, we refer to this as [targeting](https://openfeature.dev/specification/glossary#targeting). |
| 120 | +If the flag management system you're using supports targeting, you can provide the input data using the [evaluation context](https://openfeature.dev/docs/reference/concepts/evaluation-context). |
| 121 | + |
| 122 | +```ts |
| 123 | +// set a value to the global context |
| 124 | +OpenFeature.setContext({ region: "us-east-1" }); |
| 125 | + |
| 126 | +// set a value to the client context |
| 127 | +const client = OpenFeature.getClient(); |
| 128 | +client.setContext({ version: process.env.APP_VERSION }); |
| 129 | + |
| 130 | +// set a value to the invocation context |
| 131 | +const requestContext = { |
| 132 | + targetingKey: req.session.id, |
| 133 | + email: req.session.email, |
| 134 | + product: req.productId |
| 135 | +}; |
| 136 | + |
| 137 | +const boolValue = await client.getBooleanValue('some-flag', false, requestContext); |
| 138 | +``` |
| 139 | + |
| 140 | +### Hooks |
| 141 | + |
| 142 | +[Hooks](https://openfeature.dev/docs/reference/concepts/hooks) allow for custom logic to be added at well-defined points of the flag evaluation life-cycle |
| 143 | +Look [here](https://openfeature.dev/ecosystem/?instant_search%5BrefinementList%5D%5Btype%5D%5B0%5D=Hook&instant_search%5BrefinementList%5D%5Bcategory%5D%5B0%5D=Server-side&instant_search%5BrefinementList%5D%5Btechnology%5D%5B0%5D=JavaScript) for a complete list of available hooks. |
| 144 | +If the hook you're looking for hasn't been created yet, see the [develop a hook](#develop-a-hook) section to learn how to build it yourself. |
| 145 | + |
| 146 | +Once you've added a hook as a dependency, it can be registered at the global, client, or flag invocation level. |
| 147 | + |
| 148 | +```ts |
| 149 | +import { OpenFeature } from "@openfeature/js-sdk"; |
| 150 | + |
| 151 | +// add a hook globally, to run on all evaluations |
| 152 | +OpenFeature.addHooks(new ExampleGlobalHook()); |
| 153 | + |
| 154 | +// add a hook on this client, to run on all evaluations made by this client |
| 155 | +const client = OpenFeature.getClient(); |
| 156 | +client.addHooks(new ExampleClientHook()); |
| 157 | + |
| 158 | +// add a hook for this evaluation only |
| 159 | +const boolValue = await client.getBooleanValue("bool-flag", false, { hooks: [new ExampleHook()]}); |
| 160 | +``` |
| 161 | + |
| 162 | +### Logging |
| 163 | + |
| 164 | +The JS SDK will log warning and errors to the console by default. |
| 165 | +This behavior can be overridden by passing a custom logger either globally or per client. |
| 166 | +A custom logger must implement the [Logger interface](../shared/src/logger/logger.ts). |
| 167 | + |
| 168 | +```ts |
| 169 | +import type { Logger } from "@openfeature/js-sdk"; |
| 170 | + |
| 171 | +// The logger can be anything that conforms with the Logger interface |
| 172 | +const logger: Logger = console; |
| 173 | + |
| 174 | +// Sets a global logger |
| 175 | +OpenFeature.setLogger(logger); |
| 176 | + |
| 177 | +// Sets a client logger |
| 178 | +const client = OpenFeature.getClient(); |
| 179 | +client.setLogger(logger); |
| 180 | +``` |
| 181 | + |
| 182 | +### Named clients |
| 183 | + |
| 184 | +Clients can be given a name. |
| 185 | +A name is a logical identifier which can be used to associate clients with a particular provider. |
| 186 | +If a name has no associated provider, the global provider is used. |
| 187 | + |
| 188 | +```ts |
| 189 | +import { OpenFeature, InMemoryProvider } from "@openfeature/js-sdk"; |
| 190 | + |
| 191 | +const myFlags = { |
| 192 | + 'v2_enabled': { |
| 193 | + variants: { |
| 194 | + on: true, |
| 195 | + off: false |
| 196 | + }, |
| 197 | + disabled: false, |
| 198 | + defaultVariant: "on" |
| 199 | + } |
| 200 | +}; |
| 201 | + |
| 202 | +// Registering the default provider |
| 203 | +OpenFeature.setProvider(InMemoryProvider(myFlags)); |
| 204 | +// Registering a named provider |
| 205 | +OpenFeature.setProvider("otherClient", new InMemoryProvider(someOtherFlags)); |
| 206 | + |
| 207 | +// A Client backed by default provider |
| 208 | +const clientWithDefault = OpenFeature.getClient(); |
| 209 | +// A Client backed by NewCachedProvider |
| 210 | +const clientForCache = OpenFeature.getClient("otherClient"); |
| 211 | +``` |
| 212 | + |
| 213 | +### Eventing |
| 214 | + |
| 215 | +Events allow you to react to state changes in the provider or underlying flag management system, such as flag definition changes, provider readiness, or error conditions. |
| 216 | +Initialization events (`PROVIDER_READY` on success, `PROVIDER_ERROR` on failure) are dispatched for every provider. |
| 217 | +Some providers support additional events, such as `PROVIDER_CONFIGURATION_CHANGED`. |
| 218 | + |
| 219 | +Please refer to the documentation of the provider you're using to see what events are supported. |
| 220 | + |
| 221 | +```ts |
| 222 | +import { OpenFeature, ProviderEvents } from '@openfeature/js-sdk'; |
| 223 | + |
| 224 | +// OpenFeature API |
| 225 | +OpenFeature.addHandler(ProviderEvents.Ready, (eventDetails) => { |
| 226 | + console.log(`Ready event from: ${eventDetails?.clientName}:`, eventDetails); |
| 227 | +}); |
| 228 | + |
| 229 | +// Specific client |
| 230 | +const client = OpenFeature.getClient(); |
| 231 | +client.addHandler(ProviderEvents.Error, (eventDetails) => { |
| 232 | + console.log(`Error event from: ${eventDetails?.clientName}:`, eventDetails); |
| 233 | +}); |
| 234 | +``` |
| 235 | + |
| 236 | +### Shutdown |
| 237 | + |
| 238 | +The OpenFeature API provides a close function to perform a cleanup of all registered providers. |
| 239 | +This should only be called when your application is in the process of shutting down. |
| 240 | + |
| 241 | +```ts |
| 242 | +import { OpenFeature } from '@openfeature/js-sdk'; |
| 243 | + |
| 244 | +await OpenFeature.close() |
| 245 | +``` |
| 246 | + |
| 247 | +## Extending |
| 248 | + |
| 249 | +### Develop a provider |
| 250 | + |
| 251 | +To develop a provider, you need to create a new project and include the OpenFeature SDK as a dependency. |
| 252 | +This can be a new repository or included in [the existing contrib repository](https://github.com/open-feature/js-sdk-contrib) available under the OpenFeature organization. |
| 253 | +You’ll then need to write the provider by implementing the [Provider interface](./src/provider/provider.ts) exported by the OpenFeature SDK. |
| 254 | + |
| 255 | +```ts |
| 256 | +import { JsonValue, Provider, ResolutionDetails } from '@openfeature/js-sdk'; |
| 257 | + |
| 258 | +// implement the provider interface |
| 259 | +class MyProvider implements Provider { |
| 260 | + |
| 261 | + readonly metadata = { |
| 262 | + name: 'My Provider', |
| 263 | + } as const; |
| 264 | + |
| 265 | + // Optional provider managed hooks |
| 266 | + hooks?: Hook<FlagValue>[]; |
| 267 | + |
| 268 | + resolveBooleanEvaluation(flagKey: string, defaultValue: boolean, context: EvaluationContext, logger: Logger): Promise<ResolutionDetails<boolean>> { |
| 269 | + // code to evaluate a boolean |
| 270 | + } |
| 271 | + |
| 272 | + resolveStringEvaluation(flagKey: string, defaultValue: string, context: EvaluationContext, logger: Logger): Promise<ResolutionDetails<string>> { |
| 273 | + // code to evaluate a string |
| 274 | + } |
| 275 | + |
| 276 | + resolveNumberEvaluation(flagKey: string, defaultValue: number, context: EvaluationContext, logger: Logger): Promise<ResolutionDetails<number>> { |
| 277 | + // code to evaluate a number |
| 278 | + } |
| 279 | + |
| 280 | + resolveObjectEvaluation<T extends JsonValue>(flagKey: string, defaultValue: T, context: EvaluationContext, logger: Logger): Promise<ResolutionDetails<T>> { |
| 281 | + // code to evaluate an object |
| 282 | + } |
| 283 | + |
| 284 | + status?: ProviderStatus | undefined; |
| 285 | + events?: OpenFeatureEventEmitter | undefined; |
| 286 | + |
| 287 | + initialize?(context?: EvaluationContext | undefined): Promise<void> { |
| 288 | + // code to initialize your provider |
| 289 | + } |
| 290 | + |
| 291 | + onClose?(): Promise<void> { |
| 292 | + // code to shut down your provider |
| 293 | + } |
| 294 | +} |
| 295 | +``` |
| 296 | + |
| 297 | +> Built a new provider? [Let us know](https://github.com/open-feature/openfeature.dev/issues/new?assignees=&labels=provider&projects=&template=document-provider.yaml&title=%5BProvider%5D%3A+) so we can add it to the docs! |
| 298 | +
|
| 299 | +### Develop a hook |
| 300 | + |
| 301 | +To develop a hook, you need to create a new project and include the OpenFeature SDK as a dependency. |
| 302 | +This can be a new repository or included in [the existing contrib repository](https://github.com/open-feature/js-sdk-contrib) available under the OpenFeature organization. |
| 303 | +Implement your own hook by conforming to the [Hook interface](../shared/src/hooks/hook.ts). |
| 304 | + |
| 305 | +```ts |
| 306 | +import type { Hook, HookContext, EvaluationDetails, FlagValue } from "@openfeature/js-sdk"; |
| 307 | + |
| 308 | +export class MyHook implements Hook { |
| 309 | + after(hookContext: HookContext, evaluationDetails: EvaluationDetails<FlagValue>) { |
| 310 | + // code that runs when there's an error during a flag evaluation |
| 311 | + } |
| 312 | +} |
| 313 | +``` |
| 314 | + |
| 315 | +> Built a new hook? [Let us know](https://github.com/open-feature/openfeature.dev/issues/new?assignees=&labels=hook&projects=&template=document-hook.yaml&title=%5BHook%5D%3A+) so we can add it to the docs! |
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