Rounding Issues when converting Millimeter to Centimeter

[baumi951]

Rounding Issues when converting Millimeter to Centimeter

[glepretre]

Use toPrec https://github.com/gentooboontoo/js-quantities#rounding

Qty(222224, "mm").to("cm").toPrec('mm').scalar
22222.4

[baumi951]

Thanks @glepretre i think thats a good Quick Solution for most cases.

But for me it does not really solve the root rounding problem. Because i have to define a rounding precission inside my source code but i dont know how many decimal places the user may enter.

The user may also input a value of 222224.123 mm and want to calculate it to centimeter then the expected output is 22222.4123

console.log("222224.123 mm to cm", Qty(222224.123, "mm").to("cm").scalar)
Output
22222.4123
✔ This works fine somehow

But if i use .toPrec i have to define a maximum precission
console.log("222224.123 mm to cm", Qty(222224.123, "mm").to("cm").toPrec(0.001).scalar)
Output
22222.412
❌ the last digit is missing, i have to define the prec even smaller

So i would have to define a toPrec something like this: .toPrec(0.00000001) which is just simply super hacky because it is a magic number

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I really expect that the js-quantities framwork just simply outputs 22222.4 instead of 22222.399999999998 by default, it is just a division through 10

[baumi951]

I think the issue can be closed, because it's a javascript internal behavior to have some weird precision "issues" sometimes:
https://stackoverflow.com/questions/963873/1-265-10000-126499-99999999999

I think it's not job of this libary to fix it, with round we have a good workaround