@profullstack/text-type-detection

A lightweight, zero-dependency Node.js module for detecting text format types from strings. Accurately identifies plain text, markdown, ASCII art, code blocks, HTML, JSON, and XML.

Features

• 🎯 Accurate Detection: Uses multiple heuristics to identify text formats
• 🚀 Zero Dependencies: Pure JavaScript implementation
• 📦 ESM Support: Modern ES Module syntax
• 🧪 Well Tested: Comprehensive test coverage with Mocha and Chai
• 🎨 ASCII Art Detection: Recognizes box drawing, Unicode art, ANSI sequences
• 📝 Markdown Support: Detects headings, lists, links, code blocks, and more
• 🔍 Multiple Formats: Supports plain, markdown, ascii, code, html, json, xml

Installation

pnpm add @profullstack/text-type-detection

Or with npm:

npm install @profullstack/text-type-detection

Usage

Basic Example

import { detectTextFormat } from '@profullstack/text-type-detection';

const text = '# Hello World\n\nThis is a markdown document.';
const result = detectTextFormat(text);

console.log(result);
// {
//   text_format: 'markdown',
//   asciiArt: 0.000,
//   markdown: 0.180,
//   reasons: {
//     ascii: [],
//     markdown: ['heading'],
//     codePenaltyApplied: false
//   },
//   stats: { lines: 3, mean: 20.67, std: 12.34, symD: 0.05, alpha: 0.75 }
// }

Detecting Different Formats

Plain Text

const plainText = 'This is just a simple sentence.';
const result = detectTextFormat(plainText);
console.log(result.text_format); // 'plain'

Markdown

const markdown = `# Title

## Subtitle

- Item 1
- Item 2

[Link](https://example.com)`;

const result = detectTextFormat(markdown);
console.log(result.text_format); // 'markdown'
console.log(result.reasons.markdown); // ['heading', 'list', 'link']

ASCII Art

const asciiArt = `┌─────────────┐
│   Hello     │
│   World     │
└─────────────┘`;

const result = detectTextFormat(asciiArt);
console.log(result.text_format); // 'ascii'
console.log(result.asciiArt); // 0.680 (high score)

Code Block

const code = `\`\`\`javascript
function hello() {
  console.log("Hello");
}
\`\`\``;

const result = detectTextFormat(code);
console.log(result.text_format); // 'code'

HTML

const html = '<div class="container"><p>Hello World</p></div>';
const result = detectTextFormat(html);
console.log(result.text_format); // 'html'

JSON

const json = '{"name": "John", "age": 30}';
const result = detectTextFormat(json);
console.log(result.text_format); // 'json'

XML

const xml = '<?xml version="1.0"?><root><item>test</item></root>';
const result = detectTextFormat(xml);
console.log(result.text_format); // 'xml'

API

detectTextFormat(text: string): DetectionResult

Analyzes the input text and returns a detection result object.

Parameters

• text (string): The text to analyze

Returns

An object with the following properties:

• text_format (string): The detected format type

  • 'plain' - Plain text
  • 'markdown' - Markdown formatted text
  • 'ascii' - ASCII art or box drawing
  • 'code' - Code block (fenced)
  • 'html' - HTML markup
  • 'json' - JSON data
  • 'xml' - XML document

• asciiArt (number): ASCII art confidence score (0.000 - 1.000)

• markdown (number): Markdown confidence score (0.000 - 1.000)

• reasons (object): Detailed detection reasons

  • ascii (array): List of ASCII art indicators found
  • markdown (array): List of markdown features found
  • codePenaltyApplied (boolean): Whether code penalty was applied

• stats (object): Statistical analysis of the text

  • lines (number): Number of lines
  • mean (number): Mean line length
  • std (number): Standard deviation of line lengths
  • symD (number): Symbol density ratio
  • alpha (number): Alphanumeric character ratio

Detection Heuristics

ASCII Art Detection

The module detects ASCII art using multiple indicators:

• Unicode Art Characters: Box drawing (U+2500-U+257F), block elements (U+2580-U+259F), Braille patterns (U+2800-U+28FF), geometric shapes (U+25A0-U+25FF)
• Border Lines: Lines composed primarily of border characters (+, -, |, _, =, etc.)
• Consistent Width: Lines with similar lengths (low standard deviation)
• Symbol Density: High ratio of symbols to alphanumeric characters
• Character Runs: Repeated sequences of the same character
• ANSI Sequences: Terminal color codes and formatting
• Trailing Spaces: Intentional spacing for alignment

Markdown Detection

Markdown features detected include:

• Headings: ATX-style (#) and Setext-style (underlined)
• Lists: Unordered (-/*/+) and ordered (1.)
• Links: [text](url) format
• Images: ![alt](url) format
• Code: Inline backticks and fenced code blocks
• Blockquotes: Lines starting with >
• Tables: Pipe-separated columns
• Emphasis: Bold (**) and italic (*)
• Horizontal Rules: ---, ***, ___
• Front Matter: YAML metadata blocks

Code Detection

Code blocks are identified by:

• Fenced code blocks (``` or ~~~)
• Indentation patterns
• Programming language keywords
• Syntax characters (semicolons, braces, brackets)

Development

Setup

# Clone the repository
git clone https://github.com/profullstack/text-type-detection.git
cd text-type-detection

# Install dependencies
pnpm install

Running Tests

# Run all tests
pnpm test

# Run tests in watch mode
pnpm run test:watch

Linting and Formatting

# Run ESLint
pnpm run lint

# Fix linting issues
pnpm run lint:fix

# Format code with Prettier
pnpm run format

Requirements

• Node.js >= 20.0.0
• ESM support

License

MIT

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Author

Profullstack, Inc. https://profullstack.com

Repository

https://github.com/profullstack/text-type-detection