@ttoss/react-feature-flags

React Feature Flags is a library that allows you to easily add feature flags to your React application using ttoss ecosystem.

Installation

pnpm add @ttoss/react-feature-flags

Getting started

Initialize the library by wrapping your application with FeatureFlagsProvider and passing loadFeatures function as a prop (loadFeatures is not required). loadFeatures function should return a promise that resolves to an object with feature flags.

import {
  FeatureFlagsProvider,
  useFeatureFlag,
} from '@ttoss/react-feature-flags';

/**
 * Load features from your backend or any other source.
 */
const loadFeatures = async () => {
  const response = await fetch('https://...');
  const { features } = await response.json();
  return features; // features is string[]
};

const App = () => {
  return (
    <FeatureFlagsProvider loadFeatures={loadFeatures}>
      <MyComponent />
    </FeatureFlagsProvider>
  );
};

Use useFeatureFlag hook to get a feature flag value.

import { useFeatureFlag } from '@ttoss/react-feature-flags';

const MyComponent = () => {
  const isFeatureEnabled = useFeatureFlag('my-feature');
  return <div>{isFeatureEnabled ? 'Enabled' : 'Disabled'}</div>;
};

Usage

useFeatureFlag hook

You can use useFeatureFlag hook to get a feature flag value. It returns true if the feature flag is enabled, false otherwise.

import { useFeatureFlag } from '@ttoss/react-feature-flags';

const MyComponent = () => {
  const isFeatureEnabled = useFeatureFlag('my-feature');
  return <div>{isFeatureEnabled ? 'Enabled' : 'Disabled'}</div>;
};

FeatureFlag component

You can use FeatureFlag component to render its children only if the feature flag is enabled. It has a fallback (optional) prop that can be used to render something else if the feature flag is disabled.

import { FeatureFlag } from '@ttoss/react-feature-flags';

const MyComponent = () => {
  return (
    <FeatureFlag name="my-feature" fallback={<div>Feature is disabled</div>}>
      <div>Feature is enabled</div>
    </FeatureFlag>
  );
};

Update feature flags

You can update feature flags by calling updateFeatures function that is returned from useFeatureFlags hook. This is useful when you want to update feature flags after providers are initialized.

import { useFeatureFlags } from '@ttoss/react-feature-flags';

const MyComponent = () => {
  const { updateFeatures } = useFeatureFlags();
  const handleClick = async () => {
    const response = await fetch('https://...');
    const { features } = await response.json();
    updateFeatures(features);
  };
  return <button onClick={handleClick}>Update features</button>;
};

TypeScript

If you are using TypeScript, you can define your feature flags names on feature-flags.d.ts file.

import '@ttoss/react-feature-flags';

declare module '@ttoss/react-feature-flags' {
  export type FeatureFlags = 'my-feature' | 'my-other-feature';
}

This will allow you to use useFeatureFlag hook with type safety.

import { useFeatureFlag } from '@ttoss/react-feature-flags';

const MyComponent = () => {
  const isFeatureEnabled = useFeatureFlag('my-feature');
  return <div>{isFeatureEnabled ? 'Enabled' : 'Disabled'}</div>;
};