BigDecimal.js

BigInt based BigDecimal implementation for Node.js 10.4 and above. This implementation is inspired from java BigDecimal class. This implementation is faster than popular big decimal libraries for most operations. See benchmarks results part below for comparison of each operation.

Advantages of this library

• Faster than other BigDecimal libraries because of native BigInt
• Simple API that is almost same with Java's BigDecimal
• No dependencies
• Well tested
• Includes type definition file

Installation

npm install bigdecimal.js

Usage

• The example usage is given below:

const { Big } = require('bigdecimal.js');

// Single constructor for all values
// Construct from a string and copy it

const x = Big('1.1111111111111111111111');
const y = new Big(x); // you can also use 'new'

const z = x.add(y);
console.log(z.toString()); // 2.2222222222222222222222

// You can also construct from a number or BigInt:

const u = Big(1.1);
const v = Big(2n);

console.log(u.toString()); // 1.1
console.log(v.toString()); // 2

You can use MathContext to set precision and rounding mode for a specific operation:

const { Big, MC, RoundingMode } = require('bigdecimal.js');

const x = Big('1');
const y = Big('3');

const res1 = x.divide(y, MC(3)); // MC is MathContext constructor that can be used without `new`
console.log(res1.toString()); // 0.333

const res2 = x.divide(y, new MC(3, RoundingMode.UP));
console.log(res2.toString()); // 0.334

try {
    x.divide(y);
    // throws since full precision is requested but it is not possible
} catch (e) {
    console.log(e); // RangeError: Non-terminating decimal expansion; no exact representable decimal result.
}

Documentation

• API Documentation

Testing

• Install dependencies: npm i
• Compile: npm run compile
• Run tests: npm test

Running Benchmarks

There is a benchmark suite that compares

• This library
• big.js
• GWT based BigDecimal

To run the benchmark run npm install and then npm run benchmark.

Benchmark Results

For now, benchmarked against big.js and bigdecimal.

• Test Machine:

  • M1 2020 Macbook Air
  • 8 GB Ram
  • MacOS Monterey 12.0.1

• Update Date: January 7th 2022

• Library versions used:

  • big.js 6.1.1
  • (this library) bigdecimal.js 1.1.1
  • bigdecimal 0.6.1

• Each operation is run with fixed set of decimal numbers composed of both simple and complex numbers.

• Micro benchmark framework used is benchmark. Check out benchmarks folder for source code of benchmarks.

• For now, benchmarked the following operations, all operations will be added soon.

• Operations per second(op/s):

Operation	Bigdecimal.js	Big.js	GWT	Winner
Add	79,130	18,675	85.21	BigDecimal.js
Multiply	495,894	33,534	2,607	BigDecimal.js
Subtract	72,754	18,190	88.47	BigDecimal.js
Divide	15,123	1,122	658	BigDecimal.js
Abs	751,232	1,405,722	13,732	Big.js
Compare	529,009	1,152,995	1,010,368	Big.js
Remainder	9,705	3,878	2,487	BigDecimal.js