List languages and themes

Language metadata includes id, name, parser, aliases, extensions, globs, Emacs modes and shebangs. Lists are sorted by id. JavaScript also includes the npm parser packageName; Elixir includes the Hex package_name.

themes.available() and Lumis.Theme.available/0 return theme names and appearances. Rust's themes::available() returns complete themes. Use themes.get(name), themes::get(name), or Lumis.Theme.get/1 to look up one theme.

import * as languages from '@lumis-sh/lumis/languages';
import * as themes from '@lumis-sh/lumis/themes';

for (const language of languages.available()) {
  const {id, name, extensions} = language
  console.log(id, name, extensions)
}

for (const theme of themes.available()) {
  console.log(theme.name, theme.appearance)
}

Look one up by name

Aliases resolve the way highlighting resolves them, so js finds JavaScript.

How an unknown name is reported follows each host's convention: JavaScript / TypeScript returns undefined and Elixir returns nil, both without raising, while Rust returns None for an unknown language and an error for an unknown theme. The CLI exits non-zero.

import * as languages from '@lumis-sh/lumis/languages';
import * as themes from '@lumis-sh/lumis/themes';

// { id: 'javascript', name: 'JavaScript', ... }
languages.get('js')
languages.get('nope')  // undefined

themes.get('catppuccin_frappe')

import frappe from '@lumis-sh/themes/catppuccin_frappe'

Find the parser package

A language id is not always its parser name. EJS and ERB both use embedded-template; MDX uses markdown. Read parser rather than building a package name from the language id. This lookup does not load the parser.

import * as languages from '@lumis-sh/lumis/languages';

languages.get('ejs')?.parser      // 'embedded-template'
languages.get('ejs')?.packageName // '@lumis-sh/wasm-embedded-template'
languages.get('mdx')?.packageName // '@lumis-sh/wasm-markdown'
languages.get('text')?.parser    // undefined

What is loaded right now

The catalog lists what Lumis knows about. This lists what can be highlighted without a download, which is a smaller set — highlighting loads what a document turns out to need.

Themes have no equivalent: every theme is compiled in, so there is nothing to load and nothing that could be missing.

import * as languages from '@lumis-sh/lumis/languages';

languages.loaded() // ['json', 'rust']