https://github.com/ether/ep_hljs
Whole-pad syntax highlighting for Etherpad via highlight.js
https://github.com/ether/ep_hljs
code developer etherpad ide plugins software
Last synced: 6 days ago
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Whole-pad syntax highlighting for Etherpad via highlight.js
- Host: GitHub
- URL: https://github.com/ether/ep_hljs
- Owner: ether
- License: apache-2.0
- Created: 2026-05-08T09:06:06.000Z (about 1 month ago)
- Default Branch: main
- Last Pushed: 2026-06-13T01:59:03.000Z (9 days ago)
- Last Synced: 2026-06-13T03:25:24.569Z (9 days ago)
- Topics: code, developer, etherpad, ide, plugins, software
- Language: JavaScript
- Homepage: https://etherpad.org
- Size: 1.77 MB
- Stars: 0
- Watchers: 0
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
- Agents: AGENTS.md
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README
# Syntax Highlighting in Etherpad
Whole-pad syntax highlighting for [Etherpad](https://etherpad.org/), powered by [highlight.js](https://highlightjs.org/).
## Features
- Auto-detects the pad's language (or pick from a toolbar dropdown).
- The chosen language is a **pad-wide** setting and syncs to all collaborators in real time.
- Per-user / pad-wide enable toggle in the settings panel.
- Configurable indent size (2 or 4 spaces) with auto-indent on Enter, Tab, and Shift+Tab when a language is set.
- Light and dark palettes — dark mode follows Etherpad's `super-dark-editor` skin variant.
- HTML and PDF exports include the highlighting (theme CSS inlined).
## Architecture
Tokens are computed at render time and painted by the browser via the [CSS Custom Highlights API](https://developer.mozilla.org/en-US/docs/Web/API/CSS_Custom_Highlight_API) — **the DOM Etherpad's editor owns is never modified**. Range objects are registered with `CSS.highlights` and styled via `::highlight(hljs-…)` rules, so:
- Your typing never disturbs your caret.
- Your collaborators' edits never disturb yours.
- No Easysync attribute broadcast — zero overhead on the changeset rail.
Highlight.js detection runs on a 2-second idle timer; the LRU-cached `hljs.highlight()` runs at line-render time keyed by `language:lineText`.
## Install
```bash
pnpm run plugins i ep_hljs
```
## Configure
Optional admin overrides in `settings.json`:
```json
"ep_hljs": {
"indent-size": 4
}
```
(`indent-size` defaults to `2`. Per-user and per-pad pickers are in the User Settings / Pad Settings panels — admins can enforce a value via this setting if desired.)
## Browser support
CSS Custom Highlights ships in:
- Chrome / Edge 105+ (Sep 2022)
- Safari 17.2+ (Dec 2023)
- Firefox 140+ (mid 2025)
On older browsers the editor still works — highlighting silently no-ops.
## Bugs / requests
[github.com/ether/ep_hljs/issues](https://github.com/ether/ep_hljs/issues)