fraction-kit

fraction-kit is a small, educational JavaScript library for exact fraction arithmetic. It keeps fractions normalized (reduced, positive denominator) and provides an immutable API.

Installation

npm install fraction-kit

Quick Start

const Fraction = require("fraction-kit");

const a = new Fraction("1/2");
const b = new Fraction(3, 4);

console.log(a.add(b).toString()); // "5/4"
console.log(a.sub("1/6").toString()); // "1/3"
console.log(a.mul(2).toString()); // "1"
console.log(a.div("2/3").toString()); // "3/4"

Constructor Inputs

You can create a Fraction from:

• Two integers: new Fraction(numerator, denominator)
• A fraction string: new Fraction("a/b")
• An integer: new Fraction(7)
• Another Fraction: new Fraction(existingFraction)

Examples:

new Fraction(2, 4).toString(); // "1/2"
new Fraction("10/-15").toString(); // "-2/3"
new Fraction(7).toString(); // "7"

Basic API

• add(value) -> returns a new Fraction
• sub(value) -> returns a new Fraction
• mul(value) -> returns a new Fraction
• div(value) -> returns a new Fraction
• equals(value) -> returns true / false
• compare(value) -> returns -1, 0, or 1
• toString() -> "a" or "a/b"
• toDecimal() -> decimal number

value can be a Fraction, integer number, or fraction string where relevant.

More Examples

Mixed input types

const Fraction = require("fraction-kit");

console.log(new Fraction("1/3").add(2).toString()); // "7/3"
console.log(new Fraction("5/6").sub("1/3").toString()); // "1/2"

Comparison and formatting

const Fraction = require("fraction-kit");

console.log(new Fraction("1/2").equals("2/4")); // true
console.log(new Fraction("1/5").compare("1/4")); // -1
console.log(new Fraction("14/49").toString()); // "2/7"
console.log(new Fraction("1/4").toDecimal()); // 0.25

Error handling

const Fraction = require("fraction-kit");

try {
  new Fraction("1/0");
} catch (error) {
  console.error(error.message); // "Denominator cannot be zero"
}