bigmathix

A lightweight, high-precision big number utility for JavaScript and Node.js. Designed for financial calculations, blockchain integrations, and any environment where native JavaScript numbers are not enough.

✨ Features

• 🔢 Arbitrary-precision math using BigInt
• ⚡ Zero dependencies — fast & secure
• 🧮 Easy-to-use math functions (add, sub, mul, div, pow, etc.)
• 🧱 Type-safe and stable
• 🔒 Suitable for cryptography, blockchain, finance, token math
• 📦 Works in Node.js and bundlers (Vite, Webpack, etc.)

📦 Installation

The library is the single JavaScript file big.js or the ES module big.mjs.

Node.js

$ npm install bigmathix

CommonJS:

const Big = require('bigmathix');

ES module:

import Big from 'bigmathix';

🚀 Usage

In the code examples below, semicolons and toString calls are not shown.

The library exports a single constructor function, Big.

A Big number is created from a primitive number, string, or other Big number.

x = new Big(123.4567)
y = Big('123456.7e-3')                 // 'new' is optional
z = new Big(x)
x.eq(y) && x.eq(z) && y.eq(z)          // true

In Big strict mode, creating a Big number from a primitive number is disallowed.

Big.strict = true
x = new Big(1)                         // TypeError: [bigmathix] Invalid number
y = new Big('1.0000000000000001')
y.toNumber()                           // Error: [bigmathix] Imprecise conversion

A Big number is immutable in the sense that it is not changed by its methods.

0.3 - 0.1                              // 0.19999999999999998
x = new Big(0.3)
x.minus(0.1)                           // "0.2"
x                                      // "0.3"

The methods that return a Big number can be chained.

x.div(y).plus(z).times(9).minus('1.234567801234567e+8').plus(976.54321).div('2598.11772')
x.sqrt().div(y).pow(3).gt(y.mod(z))    // true

Like JavaScript's Number type, there are toExponential, toFixed and toPrecision methods.

x = new Big(255.5)
x.toExponential(5)                     // "2.55500e+2"
x.toFixed(5)                           // "255.50000"
x.toPrecision(5)                       // "255.50"

The arithmetic methods always return the exact result except div, sqrt and pow (with negative exponent), as these methods involve division.

The maximum number of decimal places and the rounding mode used to round the results of these methods is determined by the value of the DP and RM properties of the Big number constructor.

Big.DP = 10
Big.RM = Big.roundHalfUp

x = new Big(2);
y = new Big(3);
z = x.div(y)                           // "0.6666666667"
z.sqrt()                               // "0.8164965809"
z.pow(-3)                              // "3.3749999995"
z.times(z)                             // "0.44444444448888888889"
z.times(z).round(10)                   // "0.4444444445"

The value of a Big number is stored in a decimal floating point format in terms of a coefficient, exponent and sign.

x = new Big(-123.456);
x.c                                    // [1,2,3,4,5,6]    coefficient (i.e. significand)
x.e                                    // 2                exponent
x.s                                    // -1               sign

For advanced usage, multiple Big number constructors can be created, each with an independent configuration.

🧠 Minify

To minify using, for example, npm and terser

$ npm install -g terser

$ terser big.js -c -m -o big.min.js

🧪 Test

The test directory contains the test scripts for each Big number method.

The tests can be run with Node.js or a browser.

Run all the tests:

$ npm test

Test a single method:

$ node test/toFixed

For the browser, see runner.html and test.html in the test/browser directory.

big-vs-number.html is a old application that enables some of the methods of bigmathix to be compared with those of JavaScript's Number type.

📝 TypeScript

The DefinitelyTyped project has a Typescript type definitions file for bigmathix.

$ npm install --save-dev @types/bigmathix

Any questions about the TypeScript type definitions file should be addressed to the DefinitelyTyped project.

📄 Licence

MIT