Something I recently came across when working with calculations which were to 4 decimal places and then had to be rounded to 2 decimal places, was rounding in Javascript.
The code that was originally doing this was toFixed(x) where x is the number of decimal places required. After some incorrect calcualtions and investigation, I found that toFixed(x) instead of rounding to 2 decimal places, was discarding anything after the 2 decimal places. More chopping rather than rounding!
Then I looked into the Math.round function to see if this would be a better alternative and it was. Using the following logic, the totals now round nicely to 2 decimal places (this can be adapted for however many decimal places are required).
Math.round(total * 10^x) / 10^x (where x is the number of decimal places required)
Therefore my code reads…
Math.round(total * 100) / 100
And this gives me 2 lovely decimal places, rounded, not chopped.
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