PrettyPi

A TypeScript library for converting numbers to their symbolic mathematical representations.

Features

• Identifies common mathematical constants (π, e, φ, etc.)
• Recognizes and formats square roots, cube roots, and other radicals
• Handles fractions with appropriate simplification
• Converts decimal approximations of trigonometric values to their exact forms
• Performs algebraic simplifications (e.g., 12·cos(π/6) → 6·√3)
• Uses a flexible expression tree for robust representation

Installation

npm install pretty-pi

Usage

import { prettyPi } from "pretty-pi";

console.log(prettyPi(Math.PI)); // "π"
console.log(prettyPi(Math.E)); // "e"
console.log(prettyPi(0.5)); // "1/2"
console.log(prettyPi(Math.sqrt(2))); // "√2"
console.log(prettyPi(2 * Math.PI)); // "2·π"
console.log(prettyPi(Math.PI / 2)); // "π/2"
console.log(prettyPi(Math.sin(Math.PI / 4))); // "√2/2"
console.log(prettyPi(Math.PI ** 2)); // "π²"
console.log(prettyPi(Math.E * Math.PI)); // "e·π"
console.log(prettyPi(12 * Math.cos(Math.PI / 6))); // "6·√3"

How It Works

The library uses an expression tree representation to model mathematical expressions, which enables sophisticated simplification logic and consistent formatting. The main components include:

• Expression Nodes: A hierarchy of node types representing different mathematical constructs (numbers, constants, operations)
• Parser: Converts numeric values to expression trees
• Simplification: Applies mathematical rules to produce the cleanest representation possible

Supported Representations

• Basic constants: π, e, φ (golden ratio)
• Fractions: 1/2, 3/4, etc.
• Powers: π², e³
• Square roots: √2, √3, etc.
• Cube roots: ∛2, ∛3, etc.
• Combinations: 2·π, π/4, π+1, etc.
• Trigonometric values: sin(π/4) → √2/2, cos(π/3) → 1/2, etc.

Development

# Install dependencies
npm install

# Run tests
npm test

# Run tests in watch mode
npm run test:watch

# Build the library
npm run build

License

MIT