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Comment by hirundo | Hacker News Reader

I'm generally not a fan of overloading fields, but we took the opportunity to add the currency code when we decided to encode monetary quantities in JSON as strings, e.g. "0.02USD". This has worked well, particularly because we use a money handling library that parses it unchanged.

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Do you always put the currency behind the number? I know some countries prefer the currency infront (e.g. USD), others behind (EUR).

But since this is not a human visible field, this is probably irrelevant, right?

It’s probably fine, but this sort of thing is why transactionAmount and transactionCurrency are better when separated. Consider the case when you’re doing some reporting from your DB based on currency; do you really want to have to deal with one string that contains both or just do a simple WHERE clause?

In our case those are indeed separate in the database, so that we can type the value as a numeric, which is very necessary for many operations. Those fields only get combined in the serialization.

I think I looked at this when I laid it out:

https://ux.stackexchange.com/questions/9105/international-cu...

So we put the ISO code at the end and ignore whitespace. But including a prefix sign as with `€1.234.567,89 EUR` would break it.

You also included localized formatting (the '.' and ',' ) in your example that'll likely break on parsing without special handling. For interchange, you'll want to avoid using localized formats, e.g. stick to the "C" locale or something specific or agreed to between the involved parties.

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