If you’ve ever built a Smart TV app, kiosk UI, or gamepad-navigable dashboard, you’ve hit the same wall: the browser’s tab order is useless, and mouse events don’t exist. You need spatial navigation — press right, focus moves right.
Most solutions reach for <code>getBoundingClientRect()</code> on every keypress. On a 30fps TV browser, that’s a forced layout recalculation every time the user taps the remote. You feel it.
<code>precursor</code>** takes a different approach: register rects once, navigate with pure math.**
**GitHub: **<a href="https://github.com/WaelHoury/precursor" target="_blank" rel="noopener nofollow">https://github.com/WaelHoury/precursor</a>

Wael Houry

Precursor is a JavaScript library for spatial navigation in non-mouse environments like Smart TV apps, kiosk UIs, and gamepad-navigable dashboards. Instead of calling getBoundingClientRect() on every keypress — which forces layout recalculations and causes performance issues on low-powered TV browsers — Precursor lets you register element rects once and then handles directional focus movement using pure math, eliminating repeated DOM reads.

Precursor: Spatial Navigation With Zero DOM Reads