VWO Feature Management and Experimentation SDK

Common errors

Warnings

Install

Imports

• init
  wrong

  const { init } = require('vwo-fme-node-sdk');

  correct

  import { init } from 'vwo-fme-node-sdk';

  While `require` syntax works, prefer ESM `import` for modern Node.js and browser environments for consistency and tree-shaking benefits. The `init` function is the primary entry point for client initialization.

• IVWOClient

  import { IVWOClient } from 'vwo-fme-node-sdk';

  This is a TypeScript interface for type-safe interaction with the VWO client instance. It's used for type annotations, not for runtime instantiation.

• Flag

  import { Flag } from 'vwo-fme-node-sdk';

  This is a TypeScript interface representing the result of a feature flag evaluation, providing methods like `isEnabled()` and `getVariable()`. Use it for type-checking flag results.

• IVWOOptions

  import { IVWOOptions } from 'vwo-fme-node-sdk';

  This TypeScript interface defines the configuration object passed to the `init()` function, ensuring type safety for your SDK initialization parameters.

Quickstart

Demonstrates initializing the VWO client, evaluating a feature flag, retrieving a variable, tracking an event, and gracefully shutting down the client in a TypeScript environment.

import { init, IVWOClient, IVWOOptions, Flag } from 'vwo-fme-node-sdk';

(async () => {
  const options: IVWOOptions = {
    accountId: process.env.VWO_ACCOUNT_ID ?? '123456',
    sdkKey: process.env.VWO_SDK_KEY ?? '32-alpha-numeric-sdk-key'
  };

  const vwoClient: IVWOClient = await init(options);

  const userContext = { id: 'unique_user_id', customData: { role: 'admin' } };
  const feature: Flag = await vwoClient.getFlag('premium_feature', userContext);

  if (feature.isEnabled()) {
    console.log('Premium feature is enabled for the user!');
    const discountLevel: number = feature.getVariable('discount_level', 0);
    console.log(`User receives a ${discountLevel}% discount.`);
  } else {
    console.log('Premium feature is not enabled.');
  }

  // Track an event after a feature decision or user action
  vwoClient.trackEvent('premium_feature_used', userContext);

  // Gracefully shut down the client in long-running processes (Node.js servers)
  vwoClient.shutdown();
})();