astro/packages/markdown/remark/src/remark-prism.ts
2022-04-02 14:15:41 -06:00

72 lines
1.7 KiB
TypeScript

import { visit } from 'unist-util-visit';
import Prism from 'prismjs';
import { addAstro } from '@astrojs/prism/internal';
import loadLanguages from 'prismjs/components/index.js';
const noVisit = new Set(['root', 'html', 'text']);
const languageMap = new Map([['ts', 'typescript']]);
function runHighlighter(lang: string, code: string) {
let classLanguage = `language-${lang}`;
if (lang == null) {
lang = 'plaintext';
}
const ensureLoaded = (lang: string) => {
if (lang && !Prism.languages[lang]) {
loadLanguages([lang]);
}
};
if (languageMap.has(lang)) {
ensureLoaded(languageMap.get(lang)!);
} else if (lang === 'astro') {
ensureLoaded('typescript');
addAstro(Prism);
} else {
ensureLoaded('markup-templating'); // Prism expects this to exist for a number of other langs
ensureLoaded(lang);
}
if (lang && !Prism.languages[lang]) {
console.warn(`Unable to load the language: ${lang}`);
}
const grammar = Prism.languages[lang];
let html = code;
if (grammar) {
html = Prism.highlight(code, grammar, lang);
}
return { classLanguage, html };
}
type MaybeString = string | null | undefined;
/** */
function transformer(className: MaybeString) {
return function (tree: any) {
const visitor = (node: any) => {
let { lang, value } = node;
node.type = 'html';
let { html, classLanguage } = runHighlighter(lang, value);
let classes = [classLanguage];
if (className) {
classes.push(className);
}
node.value = `<pre class="${classes.join(
' '
)}"><code is:raw class="${classLanguage}">${html}</code></pre>`;
return node;
};
return visit(tree, 'code', visitor);
};
}
function plugin(className: MaybeString) {
return transformer.bind(null, className);
}
export default plugin;