express-feature-flags__full-sample.js

const express = require('express');
const app = express();

const HOST = process.env.HOST || '0.0.0.0';
const PORT = process.env.PORT || 8080;

const optimizelyExpress = require('@optimizely/express');
const optimizely = optimizelyExpress.initialize({
  sdkKey: '<Your_SDK_Key>',
  datafileOptions: {
    autoUpdate: true,      // Indicates feature flags will be auto-updated based on UI changes 
    updateInterval: 1*1000 // 1 second in milliseconds
  },
  logLevel: 'info',        // Controls console logging. Can be 'debug', 'info', 'warn', or 'error'
});

app.use(optimizely.middleware);

app.get('/', function(req, res, next) {
  const isEnabled = req.optimizely.client.isFeatureEnabled(
    'hello_world',       // Feature key connecting feature to UI
    'user123',           // String ID used for random percentage-based rollout
    {
      customerId: 123,   // Attributes used for targeted audience-based rollout
      isVip: true,
    }
  );

  res.send('Optimizely Express Example: ' +  (isEnabled ? 'You got the hello world feature!' : 'Feature off.'))
});

app.listen(PORT, HOST);
console.log(`Example App Running on http://${HOST}:${PORT}`);

module.exports = app;