README.md

🏁 feature-flip

Flexible React & React Native feature flagging/flipping/toggling for simple use cases

📖 Table of Contents

• 🏁 feature-flip
  • 📖 Table of Contents
  • 👀 Background
    • Features
  • ⚙️ Install
  • 📖 Usage
    • Kitchen sink
    • Overridable value parsing
  • 📚 API
  • 💬 Contributing
  • 🪪 License

👀 Background

This package facilitates a feature flag-driven workflow within React and React Native applications. It is intended for simple use cases where a local or remote configuration object is used. If you have more complex requirements such as incremental roll-outs please take a look at services such as LaunchDarkly or Unleash.

Features

• Tiny bundle size
• TypeScript support with API docs
• React hook, HOC and render prop APIs
• Optional fallback for falsy or missing flags
• Support for nested flags with custom separator
• Overridable value parsing for unique cases such as semver

⚙️ Install

Install the package locally within you project folder with your package manager:

With npm:

npm install feature-flip

With yarn:

yarn add feature-flip

With pnpm:

pnpm add feature-flip

📖 Usage

Kitchen sink

import {
  FeatureFlipsProvider,
  FeatureFlip,
  withFeatureFlip,
  useFeatureFlip
} from "feature-flip";

const features = {
  blog: {
    header: true,
    content: {
      intro: "no"
    },
    footer: false
  }
};

const Header = () => {
  const isEnabled = useFeatureFlip("blog.header");
  return isEnabled ? <header>Header</header> : null;
};

const Intro = withFeatureFlip("content.intro")(() => <p>Intro</p>);

export default function App() {
  return (
    <FeatureFlipsProvider value={features}>
      <div>
        <Header />

        <main>
          <Intro />

          <p>This is the content</p>

          <FeatureFlip name="missing-flag">
            <p>Will not show</p>
          </FeatureFlip>
        </main>

        <FeatureFlip
          name="blog.footer"
          fallback={<footer>Fallback footer</footer>}
        >
          <footer>Footer</footer>
        </FeatureFlip>
      </div>
    </FeatureFlipsProvider>
  );
}

Overridable value parsing

By providing your own onParseValue configuration option you can handle special cases such as enable/disabling a flag based on a semantic version.

First create your custom handler:

import semver from "semver";
import { defaultValueParser } from "feature-flip";

export const parseSemverValue = (value) => {
  if (semver.valid(value)) return semver.satisfies(value);
  // If it isn't a valid semver value, handle as normal
  return defaultValueParser(value);
};

Now override the config option for your FeatureFlipsProvider:

import {parseSemverValue}  from "./parse-semver-value"

const features = {
  // ...
}

const App = () => <FeatureFlipsProvider value={features} config={{
  onParseValue: parseSemverValue
}}>
  <Component />
</FeatureFlipsProvider>

📚 API

For all configuration options, please see the API docs.

💬 Contributing

Got an idea for a new feature? Found a bug? Contributions are welcome! Please open up an issue or make a pull request.

🪪 License

MIT © Tiaan du Plessis