Bool provides simple and powerful feature management tools, giving you total control of your feature rollout. Test in production, ship code faster, simpler, safer and smarter.

Introduction

This package is our main client-side (JavaScript) SDK. It can be used directly for any JavaScript application or NodeJs server-side application. This also serves as a core package for the more specialized SDKs - for instance the React SDK.

Getting started

Install the JavaScript SDK using your package manager of choice:

// npm example
npm install @usebool/sdk-js

// yarn example
yarn add @usebool/sdk-js

// pnpm example
pnpm install @usebool/sdk-js

To use the JavaScript SDK, you will need the application key. This key will be provided in the bool dashboard and it is not a secret, meaning that there is no danger in exposing it in your client-side code.

SDK initialization

import bool from '@usebool/sdk-js';

const boolClient = bool({ idToken: YOUR_ID_TOKEN });

You are now left with fetching feature flags where you have two options. After initialization, the client exposes two functions that each in turn return a Promise: hasFeature and getFeatures.

getFeatures

// Resolves in a list of feature flags
const allFeatures = await boolClient.getFeatures();

If there are no feature flags, an empty list will be returned. In case of a faulty request the function will log a generic error saying "Feature flags could not be fetched", and will return an empty list by default.

hasFeature

// Resolves in a boolean
const myAmazingFeature = await boolClient.hasFeature('MY_AMAZING_FEATURE');

In case the feature flag cannot be found, the function will log an error saying 'Flag with key MY_AMAZING_FEATURE not found' and will return false. By returning false the function provides fallback in case of an accidental deletion of a feature flag.

Here you can find an example of how to use this SDK in a real application.

TypeScript

This package also provides typescript definitions of the following:

import {
  BoolClient,
  ClientConfig,
  FeatureFlag,
  FeatureFlagList,
} from '@usebool/sdk-js';

type BoolClient = {
  hasFeature: (featureName: string) => Promise<boolean>;
  getFeatures: () => Promise<FeatureFlag[]>;
};

type ClientConfig = {
  idToken: string;
};

type FeatureFlag = {
  id: string;
  key: string;
  name: string;
  value: boolean;
  description?: string;
};

type FeatureFlagList = {
  Bool_FeatureFlag: FeatureFlag[];
};