issue with floating point precision js

Question

I am experiencing the following bug in my JS.

(1.001 * Math.pow(10, 3))

Instead of returning 1001 this returns 1000.99999999. I am trying to eradicate this bug and have been looking at using this big.js library.

I am unsure what to do to fix this issue.

I have tried the following but it doesn't seem to work.

var x = new Big(10);
(1.001 * x.pow(3));

This produces the same bug as without the library.

[Is floating point math broken?](https://stackoverflow.com/q/588004/3993662) — baao, Sep 26 '17 at 09:13
@baao thanks! I understand it is an issue, my problem is I am unable to implement a solution — , Sep 26 '17 at 09:14

score 3 · Accepted Answer · answered Sep 26 '17 at 09:13

3

You have to use Big.js that way, I think you have to forget using conventional operators :

console.log(Big(1.001).times(Big(10).pow(3)))

<script src="https://cdnjs.cloudflare.com/ajax/libs/big.js/3.2.0/big.min.js"></script>

answered Sep 26 '17 at 09:13

Serge K.

It works here, but when I try that in the console it returns a `Big` object – Sep 26 '17 at 09:15
When I use `toPrecision` it works. however, when ive just put your answer into my code and I get returned a Big object. why am i seeing a diff value to you do you know? you get the right value but do not use `toPrecision` – Sep 26 '17 at 09:29
Because I call `console.log` which will itself call `toString` on the `Big` object. – Serge K. Sep 26 '17 at 09:37

1 Answers1