highlighter.js

import { getHighlighter } from "shiki";

const supportedLangs = [
    "bash",
    "ballerina",
    "toml",
    "yaml",
    "sh",
    "json",
    "graphql",
    "sql",
    "java",
    "xml",
    "cmd"
];

String.prototype.hashCode = function () {
    var hash = 0,
        i, chr;
    if (this.length === 0) return hash;
    for (i = 0; i < this.length; i++) {
        chr = this.charCodeAt(i);
        hash = ((hash << 5) - hash) + chr;
        hash |= 0;
    }
    return hash;
}

const highlight = async (content) => {
    const highlighter = await getHighlighter({
        theme: 'github-light',
        langs: supportedLangs,
    });

    let codes = new Map();
    const regex = /```(\w+)([\s\S]*?)```/g;
    let match = [];
    while (match = regex.exec(content)) {
        let code = match[2];
        const firstLine = code.split('/n')[0];
        const indent = firstLine.length - firstLine.trimStart().length;
        const key = code.trim().split(/\r?\n/).map(row => row.trim()).join('\n');
        code = code.split(/\r?\n/).map(row => row.substring(indent - 1)).join('\n');
        const lang = (match[1]).toLowerCase();

        codes.set(key.hashCode(), highlighter.codeToHtml(code.trim(), { lang: supportedLangs.includes(lang) ? lang : '' }));
    }
    return JSON.stringify([...codes]);
}

export { highlight };