I want to write program to get multiple of 0.10 in javascript

Question

I want to allow user to enter values which are multiple of 0.10 like below - 0.10, 0.20, 0.30....1.00, 1.10, 1.20...1.90 etc

I was checking below validation when user entering value in text box

amount % 0.10 == 0

is it correct ? or i need to round reminder ?

That should work to figure out if the entered value was, in fact, a multiple of 0.1 — domsson, Mar 01 '17 at 14:05
Possible Duplicate: http://stackoverflow.com/questions/24170181/creating-a-simple-multiplication-table — Rajesh, Mar 01 '17 at 14:06
Say hello to JS floating math :) `0.50 % 0.10 --->0.09999999999999998` — Andrey, Mar 01 '17 at 14:08
@Andrey , yes so reminder will be floating point , so this is wrong logic , what should i do to get multiple of 0.10 ? — Kalashir, Mar 01 '17 at 14:10
Possible duplicate of [Why does modulus operator return fractional number in javascript?](http://stackoverflow.com/questions/3966484/why-does-modulus-operator-return-fractional-number-in-javascript) — Andrey, Mar 01 '17 at 14:11

score 2 · Accepted Answer · edited Mar 01 '17 at 14:13

You can't use remainder (modulo) on anything but integers. In order to achieve something like that - you'll have to cast your numbers into integers.

you can do it by simply multiplying their value by 10, i.e:

1.2 x 10 = 12

then you can use javascripts Number.isInteger to verify it:

function validate(n) {
  let castedNumber = n*10;
  let isInteger = Number.isInteger(castedNumber);
  return isInteger;
}

1 Answers1