Weird SUM calculation results

Wappler General
1

Hello Wapplers,

I have pretty basic repeat where I'm calculating work hours and then after repeat I'm calculating SUM of those works.

repeat_calculation.sum('calculation_man_hour')

But I see that calculation results are weird:

"repeat_calculation": [
{
"job_id": 1,
"calculation_man_hour": null,
},
{
"job_id": 2,
"calculation_man_hour": "28.81",
},
{
"job_id": 3,
"calculation_man_hour": "95.79",
}
],
"total_man_hour": 124.60000000000001,

I've highlighted number that I'm calculating with SUM and exact SUM with bold.
Is there something I should additional tweak the SUM? This happens because of NULL result in one of the entries?

2

That’s how javascript calculations work. You can test it in your browser console as well to check the results:

Screenshot 2021-10-12 at 10.59.12

there are many articles in the internet explaining this, for example:

https://medium.com/@DominicCarmel/understanding-javascripts-weird-decimal-calculations-e65f0e1adefb

You can just apply some formatting to your result so you always get the same number of decimals.

2 Likes
3

@Teodor Thanks for a quick and precise answer.

4

Another option is multiplying by 100, to turn the decimal numbers into integers, and then dividing by 100.

image

1 Like
5

Nah, formatNumber() did what exactly need to be! :slight_smile:

6

I was only just suggesting another option. However, I think converting decimals to integers is often a better solution - eg for calculations relating to currency.