Pretext is a new browser library by former React core developer Cheng Lou that efficiently calculates the height of line-wrapped text without touching the DOM. It uses a two-step process with prepare() and layout() functions, enabling fast text rendering effects. The library is rigorously tested across multiple languages using large public domain texts like The Great Gatsby.
Background
Calculating text dimensions in browsers typically requires DOM rendering, which is performance-intensive. Pretext addresses this by using off-canvas measurements and caching.
- Source
- Simon Willison
- Published
- Mar 30, 2026 at 04:08 AM
- Score
- 6.0 / 10