Pretext.js

Pretext.js's 概要

Pretext.js is a pure JavaScript and TypeScript-first library for fast text measurement and layout without touching the DOM. It eliminates forced synchronous reflows by using Canvas for one-time glyph measurements via prepare(), followed by instant pure arithmetic layouts with layout(). Achieving ~2ms for 1,000 blocks, it supports 12+ writing systems including CJK, Arabic, Hebrew, Thai, Hindi, and Korean. Zero runtime dependencies, real font metrics, reusable handles for multiple widths. Perfect for virtual scrolling, AI chat bubbles, multilingual feeds, and performance-critical text-heavy UIs. 14k+ GitHub stars.

Pretext.js's 特徴

• Zero DOM reads after prepare()

• Real font metrics via Canvas measureText()

• Multilingual support for 12+ writing systems

• TypeScript-first with full types

• Reusable prepared handles for multiple container widths

• Zero runtime dependencies

• Pure arithmetic layout for instant results

• Accurate line breaking and bidirectional text

Pretext.js's Q&A

Pretext.js's 長所と短所

Pretext.js's 使用例

• Variable-height virtual scrolling for 10,000+ items
• Pre-computing heights for AI chat bubbles in streaming responses
• Multilingual content feeds mixing scripts like Chinese, Arabic, Korean
• Performance-critical text-heavy UIs like code editors or social feeds

Pretext.js's ターゲット・オーディエンス

• Frontend developers optimizing performance
• React and framework-agnostic UI builders
• i18n and multilingual app developers
• Virtual list and infinite scroll implementers
• AI chat interface creators

Pretext.js's 価格

Free open-source library published on npm with zero runtime dependencies. No paid tiers or subscriptions mentioned.