optimizely.js

const optimizely = require('@optimizely/optimizely-sdk');
// const defaultLogger = require('@optimizely/optimizely-sdk/lib/plugins/logger');
const rp = require('request-promise');

require('dotenv').config();

module.exports = async (req, res, next) => {
  try {
    const datafile = await rp({
      uri: `https://cdn.optimizely.com/json/${process.env.OPTIMIZELY_FS_PROJECT_ID}.json`,
      json: true,
    });
    const optimizelyClient = optimizely.createInstance({
      datafile,
      logLevel: 2,
    });
    const featureKey = 'some_feature';
    const enabled = optimizelyClient.isFeatureEnabled(featureKey, 'test');
    res.locals.features = res.locals.features || {};
    res.locals.features = {
      [featureKey]: enabled,
    };
    next();
  } catch (err) {
    next(err);
  }
};