Due nature how floating point numbers are stored in JavaScript the native javascript functions doesn't round them correctly.
Let's take 145.575 number and round it to 2 digit after comma precision:
| Code | Actual Result | Correct Result |
|---|---|---|
Math.round(145.575 * 100) / 100 | 145.57 | 145.58 |
(145.575).toFixed(2) | 145.57 | 145.58 |
On the http://stackoverflow.com/questions/10015027/javascript-tofixed-not-rounding page I've found interesting solution:
function toFixed(num, precision) {
return (+(Math.round(+(num + 'e' + precision)) + 'e' + -precision)).toFixed(precision);
}
It works correctly with any number and precision combination exception number is smaller or equals to 0.0000001.