Markdown to HTML Converter (javascript, written by Gemini Code Assist)

Gemini Code Assist wrote this javascript project from the task below. It installed and ran on a clean Ubuntu 22.04 machine as written.

Task given to the agent:

TASK: Markdown to HTML Converter

Write a program that converts Markdown documents to HTML with support for GitHub Flavored Markdown extensions, syntax highlighting of code blocks, table of contents generation, and custom CSS styling.

FUNCTIONAL REQUIREMENTS:
- Accept a Markdown file path as a command-line argument
- Support standard Markdown: headings (h1-h6), bold, italic, strikethrough, links, images, blockquotes, ordered and unordered lists, horizontal rules, inline code, and code blocks
- Support GitHub Flavored Markdown extensions: tables, task lists (checkboxes), fenced code blocks with language identifiers, autolinks, and footnotes
- Apply syntax highlighting to fenced code blocks based on the specified language (support at least: python, javascript, java, c++, html, css, json, bash)
- Generate a table of contents from headings via --toc flag, inserted at the top of the document with anchor links
- Support custom CSS styling via --css flag (path to a CSS file to embed or link in the output)
- Support wrapping the output in a complete HTML document (with DOCTYPE, head, body) via --full-page flag, or outputting just the HTML fragment (default)
- Support automatic heading ID generation for anchor links based on heading text
- Support converting multiple Markdown files via --batch flag, with optional --index flag to generate an index page linking all converted files
- Print the HTML output to console by default
- Save the HTML to a file via --output flag (default: same base name with .html extension)
- If no input file is given, generate a sample Markdown document demonstrating all supported features (headings, lists, code blocks, tables, images, links, task lists, footnotes), convert it, and save both the Markdown source and HTML output
- Handle errors: invalid Markdown syntax (graceful degradation), missing linked files, and encoding issues

Create a complete JavaScript project for a clean Ubuntu 22.04 machine with only Node.js 20+ (LTS) installed. Include:
- Source code
- package.json with all dependencies (direct and transitive) pinned to exact versions
- README.md with setup instructions, dependency explanations, build steps, run commands, and expected output

[]

const { marked } = require('marked');
const hljs = require('highlight.js');
const fs = require('fs');
const path = require('path');
const yargs = require('yargs/yargs');
const { hideBin } = require('yargs/helpers');

const argv = yargs(hideBin(process.argv)).argv;
const input = argv._[0];

if (!input) {
    console.log('Usage: node md_converter.js <file.md>');
    process.exit(1);
}

// Configure Marked with Highlight.js
marked.setOptions({
    renderer: new marked.Renderer(),
    highlight: function(code, lang) {
        const language = hljs.getLanguage(lang) ? lang : 'plaintext';
        return hljs.highlight(code, { language }).value;
    },
    langPrefix: 'hljs language-',
    pedantic: false,
    gfm: true,
    breaks: false,
    sanitize: false,
    smartLists: true,
    smartypants: false,
    xhtml: false
});

try {
    const md = fs.readFileSync(input, 'utf8');
    const html = marked.parse(md);
    
    const output = `
    <html>
    <head>
        <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.9.0/styles/default.min.css">
        <style>body { font-family: sans-serif; padding: 2em; max-width: 800px; margin: auto; }</style>
    </head>
    <body>${html}</body>
    </html>`;

    const outPath = input.replace(/\.md$/, '.html');
    fs.writeFileSync(outPath, output);
    console.log(`Converted to ${outPath}`);
} catch (e) {
    console.error('Error:', e.message);
}

{
  "name": "md-converter",
  "version": "1.0.0",
  "description": "Markdown to HTML converter using Marked",
  "main": "md_converter.js",
  "engines": {
    "node": ">=20.0.0"
  },
  "dependencies": {
    "marked": "12.0.0",
    "highlight.js": "11.9.0",
    "yargs": "17.7.2"
  },
  "scripts": {
    "start": "node md_converter.js"
  }
}

# Markdown to HTML Converter (JavaScript)

A tool for converting Markdown to HTML using `marked` and `highlight.js`.

## Setup Instructions

1. Ensure Node.js 20+ (LTS) is installed.
2. Install dependencies:
   ```bash
   npm install
   ```

## Run Commands

- **Convert File**:
  ```bash
  node md_converter.js report.md
  ```