Flagpole Node.js SDK

Server-side Node.js SDK for the Flagpole feature flag management system. Provides real-time feature flag updates, caching, Express.js middleware, decorators, and comprehensive server-side feature flag management.

Installation

npm install @flagpole/node socket.io-client node-fetch
# or
yarn add @flagpole/node socket.io-client node-fetch

Quick Start

Basic Usage

import { FlagpoleClient } from '@flagpole/node';

const client = new FlagpoleClient({
  apiKey: 'your-api-key-here',
  environments: ['development'],
  cache: {
    enabled: true,
    ttl: 300, // 5 minutes
  },
  fallbacks: {
    'new-feature': false,
  },
});

// Initialize client
await client.initialize();

// Check feature flags
const isEnabled = await client.isFeatureEnabled('new-feature');
console.log('Feature enabled:', isEnabled);

// With evaluation context
const isPremium = await client.isFeatureEnabled('premium-feature', {
  userId: 'user-123',
  userType: 'premium',
});

Express.js Integration

import express from 'express';
import {
  FlagpoleClient,
  flagpoleMiddleware,
  requireFeatureFlag,
} from '@flagpole/node';

const app = express();
const client = new FlagpoleClient({ apiKey: 'your-api-key' });

// Use middleware
app.use(flagpoleMiddleware(client));

// Protected route
app.get('/beta', requireFeatureFlag('beta-access'), (req, res) => {
  res.json({ message: 'Beta feature!' });
});

// Check flags in route handler
app.get('/dashboard', async (req, res) => {
  const showAdvanced = await req.flagpole!.isFeatureEnabled(
    'advanced-dashboard'
  );
  res.json({ advanced: showAdvanced });
});

Features

✅ Real-time Updates - WebSocket integration for instant flag changes
✅ Caching - Built-in memory cache with TTL support
✅ Express Middleware - Easy integration with Express.js applications
✅ Decorators - Method and class decorators for clean code