Reduce a number with some limit

Question

I use this code to reduce amount with a small amount:

const transfer = async (  
  amount: string
): Promise<void> => {
  
  if (parseFloat(amount) <= 0.01) {
    amount = String((2 / 100) * parseFloat(amount));
  }

  // More code here...
}

As I result I would like to get for example from 0.0000054 the result 0.0000053. But what if we have huge number like 100000000.0 The calculated percentage is too hight.

Is there some other way to reduce the number but with some very small amount no matter is it a huge or very small amount? For example is it possible to use some function which will reduce the amount with the next available number?

"The calculated percentage is too hight." What does this mean? — Scott Hunter, Mar 14 '22 at 13:07
if I calculate the amount from 1 bitcoin for example the price will be too hight. — user1285928, Mar 14 '22 at 13:08
@user1285928 you're hitting the limit of floating point number precision — evolutionxbox, Mar 14 '22 at 13:12
Does this answer your question? [Is floating point math broken?](https://stackoverflow.com/questions/588004/is-floating-point-math-broken) — evolutionxbox, Mar 14 '22 at 13:12
What about the very large number of values between 0.00000533 and 0.00000534? Your question is not at all clear. More examples of how "huge numbers" should behave, and what it is that you're trying to achieve in general, might help people provide answers. — Pointy, Mar 14 '22 at 13:12
welcome to the wonderful world of JS math where 0.00000054 is 5.4e-7 and 0.1 + 0.2 = 0.30000000000000004 — Michael Warner, Mar 14 '22 at 13:14

score 1 · Accepted Answer · answered Mar 14 '22 at 13:12

I'm not entirely confident I understand what you're asking, but I think Math.max and Math.min might be what you're looking for?

function bound(lower, upper, input) {
  return Math.max(lower, Math.min(upper, input));
}

console.log( bound(0, 100, 200) ); // > 100
console.log( bound(0, 100, -200) ); // > 0

Reduce a number with some limit

1 Answers1