HighlightLanguage¶

HighlightLanguage is a pure Kotlin catalog and helper for Highlight.js language identifiers.

It provides synchronous access to the full list of supported languages (all), curated primary languages (primary), support checking (isSupported), alias normalization (canonicalName), and file extension mapping (fromExtension).

It is a convenience API. SyntaxHighlightedCode and HighlightEngine.highlight() still accept a plain String language id, so you can always pass supported Highlight.js names directly.

Full API in Dokka:

• HighlightLanguage

When to use it¶

• You need the list of supported languages synchronously (e.g. for language pickers, sheets, or autocomplete) without initializing a WebView.
• You want to display curated common languages (primary) in quick-access UI chips.
• You want to validate whether a language name or alias is supported (isSupported).
• You want to normalize common aliases like kt, js, ts, py, sh, or html to canonical grammar names (canonicalName).
• You have filenames or file extensions and need a best-effort language id (fromExtension).

Core behavior¶

Static Language Catalog¶

• HighlightLanguage.all returns all 194 supported language identifiers in alphabetical order (including html).
• HighlightLanguage.primary returns 20 curated high-demand languages for pickers and filter chips.

// Full synchronous catalog (194 languages)
val languages = HighlightLanguage.all

// Curated primary languages for chips or pickers
val quickPickers = HighlightLanguage.primary

Alias Normalization & Validation¶

• HighlightLanguage.isSupported(language) returns true if the language, alias, or file extension is recognized.
• HighlightLanguage.canonicalName(nameOrAlias) resolves an alias or name to its canonical Highlight.js identifier.

HighlightLanguage.isSupported("kt")         // true
HighlightLanguage.isSupported("html")       // true
HighlightLanguage.isSupported("unknown")    // false

HighlightLanguage.canonicalName("kt")       // "kotlin"
HighlightLanguage.canonicalName("KOTLIN")   // "kotlin"
HighlightLanguage.canonicalName("js")       // "javascript"
HighlightLanguage.canonicalName("ts")       // "typescript"
HighlightLanguage.canonicalName("py")       // "python"
HighlightLanguage.canonicalName("sh")       // "bash"
HighlightLanguage.canonicalName("html")     // "html"
HighlightLanguage.canonicalName("unknown")  // null

File Extension Mapping¶

• fromExtension(extension) returns a Highlight.js language id or null.
• Lookup is case-insensitive and locale-safe (Locale.ROOT).
• Pass extension without a leading dot.

HighlightLanguage.fromExtension("kt")   // "kotlin"
HighlightLanguage.fromExtension("KT")   // "kotlin"
HighlightLanguage.fromExtension("py")   // "python"
HighlightLanguage.fromExtension("xyz")  // null

Recommended usage pattern¶

val file = File("MainActivity.kt")
val language = HighlightLanguage.fromExtension(file.extension) ?: "plaintext"

SyntaxHighlightedCode(
    code     = file.readText(),
    language = language,
)

Practical guidance¶

• For UI pickers and autocomplete dropdowns, use HighlightLanguage.all or HighlightLanguage.primary directly.
• Prefer HighlightLanguage.canonicalName() to normalize user input or short aliases before storing or querying.
• Prefer mapping by extension only when language is not known from other metadata.
• For unknown or mixed content, consider HighlightEngine.highlightAuto() instead.

Common pitfalls¶

• Passing extension with dot (".kt") instead of "kt".
• Forgetting a fallback path (?: "plaintext") for unknown extensions.

Supported extensions¶

The current extension-to-language map (source: HighlightLanguage.kt).