Set up JavaScript SDK

// A "context" is a data object representing users, devices, organizations, and
// other entities. You'll need this later, but you can ignore it for now.
const context = {
  kind: 'user',
  key: 'EXAMPLE_CONTEXT_KEY'
};
// This is your client-side ID.
const client = createClient('YOUR_CLIENT_SIDE_ID', context);
client.start();
const { status } = await client.waitForInitialization();
if (status === 'complete') {
  console.log('SDK successfully initialized!');
} else {
  console.error('Initialization failed');
}

import { createClient } from '@launchdarkly/js-client-sdk';
// A "context" is a data object representing users, devices, organizations, and
// other entities. You'll need this later, but you can ignore it for now.
const context = {
  kind: 'user',
  key: 'EXAMPLE_CONTEXT_KEY',
  email: 'EXAMPLE_EMAIL',
};
// This is your client-side ID.
const ldClient = createClient('YOUR_CLIENT_SIDE_ID', context);
// await start — you only need waitForInitialization() if you wait somewhere
// other than where you start the client.
await ldClient.start();
console.log('SDK successfully initialized!');
// Call trackMetric when a metric action occurs in your app —
// a click, a form submit, a page view, a custom event, whatever your metric measures.
function trackMetric(metricKey, data) {
  ldClient.track(metricKey, data);
}