JS Precision Math: Choosing big.js vs mathjs

Recently I needed precision calculations in a project. Native number decimals lose precision (0.1 + 0.2 is not 0.3). So I needed a library. I considered two options and chose mathjs.

big.js

A small, fast JavaScript library for arbitrary-precision decimal arithmetic.

Size: 5.9 KB minified, 2.7 KB gzipped

The size above is from CDN usage.

Pros

1. Small size

See here

mathjs

Math.js is an extensive math library for JavaScript and Node.js. It features a flexible expression parser with support for symbolic computation, comes with a large set of built-in functions and constants, and offers an integrated solution to work with different data types like numbers, big numbers, complex numbers, fractions, units, and matrices. Powerful and easy to use.

Size: Unpacked Size 10.2 MB

Pros

1. Expression parsing

Compatibility

Math.js works on any ES5 compatible JavaScript engine: node.js, Chrome, Firefox, Safari, Edge, and IE11.

See here

Size optimization

• If you only need numbers, you can import a specific build such as mathjs/main/esm/number instead of full mathjs.

My view

If the calculation is very simple (A * B), big.js is enough. But for complex calculations, big.js hurts readability. mathjs is more readable.

Example

Here is a formula. With mathjs you can write it like this:

But with big.js, it becomes much less readable. Size can be mitigated by CDN and caching, so I chose mathjs.

Final Thoughts

Both work. Use what fits.