How can i calculate "scale"?

[antpv]

I have currency rate like this: 0.0001234

How can i calculate "scale" and "amount" for dinero currency rate correctly?

[sarahdayan]

Hey @antpv!

Your rate has seven fraction digits, meaning you can represent as an integer with a scale of 7.

An easy way to get the amount is to then multiply your rate by 10 to the power of the scale (0.0001234 * 10**7), so in your case it would be { amount: 1234, scale: 7 }.

[antpv]

Thanks @sarahdayan!

What about converting currencies with different exponent and base values?

For example, there is a currency:
{ code: 'MRU', base: 5, exponent: 1 }

I want to convert it to currency:
{ code: 'UAH', base: 10, exponent: 2 }

I have a course (UAH to MRU) from exchange rate service 0.727655

Using your function I generated rate

{
  UAH: { amount: 727655, scale: 6 }
}

But when converting i get 7.27 UAH, instead of 0.27 UAH

[sarahdayan]

There seems to be an issue when converting between currencies with different bases, thank you for catching it @antpv! I'm creating an issue now and will look into it.

[sarahdayan]

Issue open: #477

If you're interested in picking it up @antpv feel free!