Working with accurate currency values in Javascript

Question

I'm working on a system that uses financial data. I'm getting subtle rounding errors due to the use of floating point numbers. I'm wondering if there's a better way to deal with this.

One of the issues is that I'm working with a mixture of different currencies, which might have up to 12 decimals, and large numbers for other currencies.

This means that the smallest number I need to represent is 0.000000000001 * (1*10^-12) and the largest 100,000,000,000 (1*10^11).

Are there any recommended ways to work with numbers of this size and not lose precision?

what about [toFixed](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/toFixed)? — Bhojendra Rauniyar, Dec 03 '18 at 20:16
The problem is that I'm having rounding issues, I'm not really having issues with converting numbers to strings. — Evert, Dec 03 '18 at 20:22
Outside of [Decimal.js](https://mikemcl.github.io/decimal.js/) you might be better off creating a microservice written in another lang that makes use of [GMP](https://gmplib.org/) for the math. JS is not at all suited for this use case. — Chase, Dec 03 '18 at 22:15
Thanks, @Chase. Both of those are good suggestions. If you turn it into an answer, I can accept it. — Evert, Dec 03 '18 at 22:17

score 1 · Accepted Answer · answered Dec 03 '18 at 22:27

If you're really trying to stay in the JS realm you might consider Decimal.js which should cover your precision range.
If I were writing this and needed to make sure there were no rounding errors I would likely try and use a GMP extension for another lang inside a microservice which was only tasked with the financial math. GMPY2 for Python3 is probably a good bet for something quick and easy.

Working with accurate currency values in Javascript

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