Simple performance.now() polyfill for old browsers and node.

$ npm install performancenow

Make sure to import performancenow module in your application entrypoint, it will make a time stamp to measure against on every subsequent call.

import 'performancenow';

Then just import as a usual module wherever you need it.

import now from 'performancenow';

let timestamp = now();
// => 15.02

To polyfill performance.now() function.

(function (global) {
  global.performance = global.performance || {};
  global.performance.now = global.performance.now || require('performancenow');
}).call(this);

$ npm test

MIT