# lux.js - real user monitoring ![](https://img.shields.io/bundlephobia/minzip/%40speedcurve%2Flux) ![](https://img.shields.io/bundlephobia/min/%40speedcurve%2Flux) This repository contains the source code for lux.js, [SpeedCurve's real user monitoring (RUM)](https://www.speedcurve.com/) script. ## How to use lux.js 1. [Sign up for a SpeedCurve account](https://www.speedcurve.com/) 2. Go to the **Settings** page and scroll to the bottom of the page 3. Click on **Edit RUM** 4. Click on the **JS Snippet** tab 5. Copy the RUM JS snippet into the `` of your page > ⚠️ Self-hosting lux.js is not recommended. Please read our [self-hosting documentation](https://support.speedcurve.com/docs/self-hosted-real-user-monitoring) for more information. ## Configuring lux.js See [the lux.js API documentation](https://support.speedcurve.com/docs/rum-js-api). ## Using lux.js in a SPA See [the SPA documentation](https://support.speedcurve.com/docs/single-page-applications). ## Project goals 1. **Browser compatibility** - lux.js runs and gathers basic metrics in every browser that supports ES3, while still gathering modern metrics from evergreen browsers. 2. **Small size** - lux.js aims to be under 10 KB when minified and compressed. 3. **Low overhead** - lux.js creates only a handful of event handlers and observers. Most metrics are calculated on-demand before a beacon is sent. ## Local development - Compile the lux.js script with `npm run build` or `npm run watch` - Run the tests with `npm run test` - Check for linting errors with `npm run lint` and automatically fix them (where possible) with `npm run lint-fix` - Note: object properties beginning with an underscore (`_`) will be mangled