ConfigCat Provider

This provider is an implementation for ConfigCat a managed feature flag service.

Installation

$ npm install @openfeature/config-cat-provider

Required peer dependencies

The OpenFeature SDK is required as peer dependency.

The minimum required version of @openfeature/server-sdk currently is 1.6.0.

The minimum required version of configcat-js-ssr currently is 7.1.2.

$ npm install @openfeature/server-sdk configcat-js-ssr

Usage

The ConfigCat provider uses the ConfigCat JavaScript (SSR) SDK. This means that the provider can be used in both server (e.g. Node.js) and client (browser) applications.

It can either be created by passing the ConfigCat SDK options to ConfigCatProvider.create or the ConfigCatProvider constructor.

The available options can be found in the ConfigCat JavaScript (SSR) SDK.

Example using the default configuration

import { ConfigCatProvider } from '@openfeature/config-cat-provider';

const provider = ConfigCatProvider.create('<sdk_key>');
OpenFeature.setProvider(provider);

Example using different polling options and a setupHook

import { ConfigCatProvider } from '@openfeature/config-cat-provider';

const provider = ConfigCatProvider.create('<sdk_key>', PollingMode.LazyLoad, {
  setupHooks: (hooks) => hooks.on('clientReady', () => console.log('Client is ready!')),
});

OpenFeature.setProvider(provider);

Evaluation Context

ConfigCat only supports string values in its "evaluation context", there known as User Object.

This means that every value is converted to a string. This is trivial for numbers and booleans. Objects and arrays are converted to JSON strings that can be interpreted in ConfigCat.

ConfigCat has three known attributes, and allows for additional attributes. The following shows how the attributes are mapped:

| OpenFeature EvaluationContext Field | ConfigCat User Field | Required | |-------------------------------------|----------------------|----------| | targetingKey | identifier | yes | | email | email | no | | country | country | no | | Any Other | custom | no |

The following example shows the conversion between an OpenFeature Evaluation Context and the corresponding ConfigCat User:

OpenFeature

{
  "targetingKey": "test",
  "email": "email",
  "country": "country",
  "customString": "customString",
  "customNumber": 1,
  "customBoolean": true,
  "customObject": {
    "prop1": "1",
    "prop2": 2
  },
  "customArray": [
    1,
    "2",
    false
  ]
}

ConfigCat

{
  "identifier": "test",
  "email": "email",
  "country": "country",
  "custom": {
    "customString": "customString",
    "customBoolean": "true",
    "customNumber": "1",
    "customObject": "{\"prop1\":\"1\",\"prop2\":2}",
    "customArray": "[1,\"2\",false]"
  }
}

Events

The ConfigCat provider emits the following OpenFeature events:

• PROVIDER_READY
• PROVIDER_ERROR
• PROVIDER_CONFIGURATION_CHANGED

Building

Run nx package providers-config-cat to build the library.

Running unit tests

Run nx test providers-config-cat to execute the unit tests via Jest.