As far as I understand, it seems to sacrifice accuracy at larger numbers, for more accuracy at smaller numbers. As they say, that seems like a reasonable tradeoff, because we tend to mostly use smaller numbers in our software.
In my honest opinion though, if accuracy is a concern, I reach for decimal or integer based mathematical libraries. For example, in a JavaScript project that needed to handle currency, I used Dinero, because $0.1 + $0.2 needs to actually work properly. As far as I understand, it just does all math in integers, and then you can display it as a string in the UI or export it as an integer for storage as a realised decimal in the database.
It’s easier to just compute the smallest atomic amount of a currency, usually cents, using integers. Then display it as full dollars, pounds, euros—what have you—to the end user. For Division you need some way to account for the remainder across transactions, but that’s probably rules from accounting and not integer math.
What’s the benefit of Dinero? Is that like the financial equivalent of the iseven() dependency?
JavaScript is a bit funny and doesn’t actually have native integers… every number is a floating point, which means even whole number math gets weird sometimes. Not often, but enough that cents were lost and people were upset.
I haven’t looked at how Dinero works under the hood, but I never had any problems at all with it after we started using it. Front end works in cents, back end works in decimal, is what I’d suggest for anyone else reading this. Statically typed languages are much easier to control and you don’t need a library at all if you’re careful.
As far as I understand, it seems to sacrifice accuracy at larger numbers, for more accuracy at smaller numbers. As they say, that seems like a reasonable tradeoff, because we tend to mostly use smaller numbers in our software.
In my honest opinion though, if accuracy is a concern, I reach for decimal or integer based mathematical libraries. For example, in a JavaScript project that needed to handle currency, I used Dinero, because $0.1 + $0.2 needs to actually work properly. As far as I understand, it just does all math in integers, and then you can display it as a string in the UI or export it as an integer for storage as a realised decimal in the database.
It’s easier to just compute the smallest atomic amount of a currency, usually cents, using integers. Then display it as full dollars, pounds, euros—what have you—to the end user. For Division you need some way to account for the remainder across transactions, but that’s probably rules from accounting and not integer math.
What’s the benefit of Dinero? Is that like the financial equivalent of the iseven() dependency?
JavaScript is a bit funny and doesn’t actually have native integers… every number is a floating point, which means even whole number math gets weird sometimes. Not often, but enough that cents were lost and people were upset.
I haven’t looked at how Dinero works under the hood, but I never had any problems at all with it after we started using it. Front end works in cents, back end works in decimal, is what I’d suggest for anyone else reading this. Statically typed languages are much easier to control and you don’t need a library at all if you’re careful.