Mermaid ASCII

Convert Mermaid diagrams to ASCII art. A TypeScript library and CLI tool for rendering beautiful text-based diagrams.

Features

• 🎨 Convert Mermaid flowcharts to ASCII art
• 📦 Both library and CLI interfaces
• ⚡ TypeScript support with full type definitions
• 🔤 Pure ASCII mode for maximum compatibility
• 🎯 Unicode box drawing characters for enhanced visuals

Installation

npm install mermaid-ascii

Usage

Library Usage

import { mermaidToAscii } from 'mermaid-ascii';

const diagram = `
graph TD
  A[Start] --> B{Decision}
  B -->|Yes| C[Action 1]
  B -->|No| D[Action 2]
  C --> E[End]
  D --> E
`;

const ascii = mermaidToAscii(diagram);
console.log(ascii);

Output:

┌───────┐     ┌──────────┐     ┌──────────┐
│       │     │          │     │          │
│ Start ├────►│ Decision ├────►│ Action 1 │
│       │     │          │     │          │
└───────┘     └─────┬────┘     └─────┬────┘
                    │                │
                    │                v
                    │          ┌─────────┐
                    │          │         │
                    │          │   End   │
                    │          │         │
                    │          └─────────┘
                    │                ^
                    │                │
                    v          ┌─────┴────┐
              ┌──────────┐     │          │
              │          ├─────┤ Action 2 │
              │ Action 2 │     │          │
              └──────────┘     └──────────┘

ASCII Mode

For environments that don't support Unicode box drawing characters:

import { mermaidToAscii } from 'mermaid-ascii';

const ascii = mermaidToAscii(diagram, { useAscii: true });
console.log(ascii);

Output:

+-------+     +----------+     +----------+
|       |     |          |     |          |
| Start |---->| Decision |---->| Action 1 |
|       |     |          |     |          |
+-------+     +-----+----+     +-----+----+
                    |                |
                    |                v
                    |          +---------+
                    |          |         |
                    |          |   End   |
                    |          |         |
                    |          +---------+
                    |                ^
                    |                |
                    v          +-----+----+
              +----------+     |          |
              |          |-----|  Action  |
              | Action 2 |     |    2     |
              +----------+     +----------+

CLI Usage

# From stdin
echo "graph LR; A --> B --> C" | mermaid-ascii

# From file
mermaid-ascii -f diagram.mermaid

# ASCII mode
mermaid-ascii -f diagram.mermaid --ascii

API Reference

mermaidToAscii(input, options?)

Convert a Mermaid diagram string to ASCII art.

Parameters:

• input: string - Mermaid diagram as a string
• options?: MermaidToAsciiOptions - Optional configuration

Options:

• useAscii?: boolean - Use pure ASCII characters instead of Unicode (default: false)
• styleType?: string - Style type for the diagram (default: 'basic')

Returns: string - ASCII art representation of the diagram

Advanced Usage

For advanced use cases, you can access the core parsing and drawing functions:

import { mermaidFileToMap, Graph, DrawingCanvas } from 'mermaid-ascii';

// Parse Mermaid to internal representation
const properties = mermaidFileToMap(diagram, 'basic');

// Create and render graph
const graph = Graph.makeGraph(properties.data);
graph.setStyleClasses(properties);
graph.createMapping();
const drawingEngine = graph.draw();
const output = DrawingCanvas.drawingToString(drawingEngine.getCanvas());

Supported Mermaid Features

Currently supports:

• Basic flowcharts (graph TD, graph LR, etc.)
• Node definitions with labels
• Arrows and connections
• Multiple connections (A --> B & C)
• Chain connections (A --> B --> C)
• Self-references (A --> A)

License

MIT

Contributing

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