Swash Feature Flags SDK

🚀 Introduction

Welcome to the Swash Feature Flags SDK! 🎉

This lightweight JavaScript SDK allows you to easily integrate feature flags into your application. Whether you're rolling out new features gradually or enabling experimental functionality, Swash Feature Flags has you covered. ✅

Unlike traditional authentication-based systems, the Swash Feature Flags SDK uses API tokens for authentication. This means you don’t have to deal with JWTs manually—just grab your API token from the Swash Flag Dashboard and start using feature flags immediately! 🔐

📦 Installation

First, install the SDK using your favorite package manager:

pnpm add swash-feature-flags-sdk
# or
npm install swash-feature-flags-sdk
# or
yarn add swash-feature-flags-sdk

🔧 Basic Implementation (Works Out of the Box)

Here’s a quick setup that fetches feature flags and evaluates them for a user:

import SwashFeatureFlags from "swash-feature-flags-sdk";

const featureFlags = new SwashFeatureFlags("https://api.swashflag.com", "YOUR_API_TOKEN");

// Fetch feature flags
featureFlags.fetchFlags().then(flags => {
  console.log("Feature Flags:", flags);
});

// Evaluate a flag for a user
featureFlags.evaluateFlag("new-dashboard", { id: "user-123" }).then(isEnabled => {
  console.log(isEnabled ? "✅ Feature is enabled!" : "❌ Feature is disabled.");
});

Where do I get an API token? 🤔

• Go to the Swash Flag Dashboard.
• Navigate to the API Tokens section.
• Click "Generate API Token".
• Copy the generated token and use it in the SDK.

🚦 Fetching All Feature Flags

Retrieve all available feature flags like this:

featureFlags.fetchFlags().then(flags => {
  console.log("Feature Flags:", flags);
});

This returns an array of feature flags:

[
  {
    "id": "dark-mode",
    "name": "Dark Mode",
    "enabled": false
  },
  {
    "id": "new-dashboard",
    "name": "New Dashboard UI",
    "enabled": true
  }
]

🎯 Evaluating a Feature Flag for a User

If you want to check whether a specific user has access to a feature, use:

featureFlags.evaluateFlag("new-dashboard", { id: "user-123", location: "US" }).then(isEnabled => {
  if (isEnabled) {
    console.log("✅ Feature is enabled!");
  } else {
    console.log("❌ Feature is disabled.");
  }
});

This will return true or false depending on the flag’s targeting rules.

🚀 Caching for Performance

The SDK automatically caches feature flags after fetching them to avoid unnecessary API requests. If you want to manually refresh the cache:

featureFlags.refreshFlags().then(flags => {
  console.log("🔄 Flags refreshed:", flags);
});

How does caching work?

• The SDK stores feature flags in memory for 60 seconds (default).
• If a request is made before the cache expires, it returns cached flags instead of hitting the API.
• The cache resets on page reload, ensuring fresh data on new sessions.
• Developers can manually refresh flags anytime using refreshFlags().

🛠 Advanced Configuration

You can customize caching behavior and logging options:

const featureFlags = new SwashFeatureFlags("https://api.swashflag.com", "YOUR_API_TOKEN", 30000); // Cache for 30 seconds

Available Options:

| Option | Description | Default | |-------------|---------------------------------|----------| | cacheTime | Time (in milliseconds) before cache expires | 60000 (60s) |

❓ Need Help?

If you have any questions or run into issues, feel free to open an issue or reach out to us! 🚀

Happy coding! 🎉