Extended Code Highlight

Extended Code Highlight

Additional and configurable syntax highlighting for Obsidian code blocks.

The plugin highlights code in both Reading view and editor/Live Preview mode. It ships with built-in language definitions for missing or inconsistent code block languages, and can be extended with regex-based token rules in languages.json.

Features

• Built-in highlighting for WebAssembly text, Zig, Nix, HCL/Terraform, Kusto/KQL, AutoHotkey, GDScript, MLIR, Lean, Angular, Vue, Liquid, Less, Sass/SCSS, and Svelte.
• User-defined language highlighting through languages.json.
• Reading-view highlighting through Prism-compatible grammar registration.
• Editor-mode highlighting through CodeMirror 6 decorations.
• Live Preview code blocks remain editable.

Supported Languages

Obsidian uses different highlighting paths across Reading view, Source mode, and Live Preview. This plugin keeps the supported language set consistent across those views by registering Prism-compatible rules and applying matching editor decorations.

Example

```wat
(module
  (func $add (param $a i32) (param $b i32) (result i32)
    local.get $a
    local.get $b
    i32.add))
```

```svelte
<script lang="ts">
  export let name = "world";
</script>

{#if name}
  <h1>Hello {name}</h1>
{/if}
```

Extending Languages

Create languages.json in the plugin directory. You can copy languages.example.json as a starting point.

{
  "languages": [
    {
      "id": "mydsl",
      "aliases": ["my-dsl"],
      "tokens": [
        { "name": "comment", "pattern": ";.*", "flags": "m" },
        { "name": "keyword", "pattern": "\\b(foo|bar|baz)\\b" },
        { "name": "number", "pattern": "\\b\\d+(?:\\.\\d+)?\\b" },
        { "name": "string", "pattern": "\"(?:\\\\.|[^\"\\\\])*\"" }
      ]
    }
  ]
}

Each language supports:

• id: Primary fence name.
• aliases: Optional additional fence names.
• tokens: Ordered token rules.

Each token supports:

• name: CSS/token class, such as comment, keyword, string, number, builtin, variable, function, property, or operator.
• pattern: JavaScript regular expression source.
• flags: Optional regular expression flags.
• lookbehind / greedy: Optional Prism-compatible flags.

After editing languages.json, run Reload extended highlight languages, use the plugin settings reload button, or disable and re-enable the plugin.

Implementation

Obsidian uses PrismJS for Reading view code block highlighting, while Source mode and Live Preview use CodeMirror. Extended Code Highlight bridges those views with built-in language definitions and user-provided regex token definitions.

The current implementation is parser-first for built-in languages where parser support is available:

• Reading view prefers the current PrismJS grammar for a supported fence name, and falls back to the plugin's regex grammar when Prism does not provide that language.
• Editor and Live Preview prefer CodeMirror/Lezer parsers for built-in languages with bundled CodeMirror language support.
• If CodeMirror support is unavailable for a built-in language, editor highlighting falls back to the regex token rules.
• User-defined languages in languages.json always use regex token rules in both Reading view and editor/Live Preview mode.

Installation

Copy the built plugin files into:

<your-vault>/.obsidian/plugins/extended-code-highlight/

Required files:

manifest.json
main.js
styles.css

Then enable Extended Code Highlight from Obsidian's Community plugins settings.

Styling

Reading view tokens use Prism-style classes:

<span class="token keyword">...</span>

Editor tokens use CodeMirror decoration classes:

extended-code-highlight-editor-keyword

Customize colors in styles.css.

Development

pnpm install
pnpm run build

Watch mode:

pnpm run dev

main.js is committed so the plugin can be installed directly without rebuilding.

Troubleshooting

• Reload the plugin after changing files.
• Switch away from the note and back if editor decorations do not refresh.
• Run Reload extended highlight languages after editing languages.json.
• Check Obsidian's developer console for plugin load errors.
• If Live Preview code blocks become uneditable, make sure the plugin version does not use registerMarkdownCodeBlockProcessor for normal highlighting.