rumdl-wasm

Fast markdown linter with 60+ rules, compiled to WebAssembly.

Installation

npm install rumdl-wasm

Quick Start

import init, { lint_markdown, apply_all_fixes } from 'rumdl-wasm';

// Initialize the WASM module
await init();

// Lint markdown content
const content = '# Hello World\n\nSome text here...';
const warnings = JSON.parse(lint_markdown(content));

// Apply all auto-fixes
const fixed = apply_all_fixes(content);

API Reference

init()

Initialize the WASM module. Must be called before using other functions.

await init();

lint_markdown(content: string): string

Lint markdown content and return warnings as JSON.

const warnings = JSON.parse(lint_markdown(content));

Returns a JSON array of warnings (see Warning Format below).

apply_all_fixes(content: string): string

Apply all available auto-fixes to the content.

const fixed = apply_all_fixes(content);

Returns the fixed content string.

apply_fix(content: string, fix_json: string): string

Apply a single fix to the content.

const fix = JSON.stringify({ start: 0, end: 5, replacement: 'Hello' });
const fixed = apply_fix(content, fix);

get_version(): string

Get the rumdl version.

const version = get_version(); // e.g., "0.0.185"

get_available_rules(): string

Get list of available rules as JSON.

const rules = JSON.parse(get_available_rules());
// [{ name: "MD001", description: "Heading levels should only increment by one level at a time" }, ...]

Warning Format

Each warning object contains:

interface Warning {
  rule: string;        // Rule name (e.g., "MD001")
  message: string;     // Warning message
  line: number;        // 1-indexed line number
  column: number;      // 1-indexed column number
  end_line: number;    // 1-indexed end line
  end_column: number;  // 1-indexed end column
  severity: string;    // "Error" or "Warning"
  fix?: {              // Optional auto-fix
    start: number;     // Byte offset start
    end: number;       // Byte offset end
    replacement: string;
  };
}

Browser Usage

ES Module

<script type="module">
  import init, { lint_markdown } from './rumdl_wasm.js';

  async function main() {
    await init();
    const warnings = JSON.parse(lint_markdown('# Test'));
    console.log(warnings);
  }

  main();
</script>

With CDN (unpkg)

<script type="module">
  import init, { lint_markdown } from 'https://unpkg.com/rumdl-wasm/rumdl_wasm.js';

  await init();
  console.log(JSON.parse(lint_markdown('# Test')));
</script>

Node.js Usage

import init, { lint_markdown, apply_all_fixes } from 'rumdl-wasm';
import { readFile } from 'fs/promises';

await init();

const content = await readFile('README.md', 'utf-8');
const warnings = JSON.parse(lint_markdown(content));

for (const w of warnings) {
  console.log(`${w.line}:${w.column} ${w.rule} ${w.message}`);
}

Bundler Usage

Vite

// vite.config.js
export default {
  optimizeDeps: {
    exclude: ['rumdl-wasm']
  }
};

// main.js
import init, { lint_markdown } from 'rumdl-wasm';

await init();
const warnings = JSON.parse(lint_markdown(content));

Webpack 5

// webpack.config.js
module.exports = {
  experiments: {
    asyncWebAssembly: true
  }
};

TypeScript

TypeScript definitions are included. The package exports all functions with proper types.

import init, { lint_markdown, apply_all_fixes, get_version } from 'rumdl-wasm';

await init();

const warnings: Warning[] = JSON.parse(lint_markdown(content));
const fixed: string = apply_all_fixes(content);
const version: string = get_version();

License

MIT