big-number.js is large number calculator for JavaScript.
This module can perform basic arithmetic operations - addition, subtraction, multiplication and (soon enough) division - on arbitrarily large integers. Theoretically, it can perform calculations on any integer smaller than infinity, but of course, the browser engine and memory capability of the user's machine might limit it to smaller integers.
In JavaScript, a string can theoretically be infinitely long, and this is what the module exploits in order to perform these tasks.