jonplussed / purescript-number-format Goto Github PK

Re #1
What are your thoughts for providing some safe versions that aren't wrapped in a Maybe or in an Eff? Only for the more common choices. Stuff like toBinString :: Number -> String or toHexString :: Number -> String would be pretty nice to have.

Pretty easy to implement as well:

toBinString :: Number -> String
toBinString = fromJust <<< toString "2"

toHexString :: Number -> String
toHexString = fromJust <<< toString "16"

These modules are unsafe from a compilation standpoint. For more info see here: https://github.com/purescript/purescript/wiki/FFI-tips#avoid-calling-ps-code-from-within-js-directly

Culprits are lines like: https://github.com/Jonplussed/purescript-number-format/blob/master/src/Number/Format/Maybe.purs#L14

Should be as simple as taking the Just/Nothing functions into the ffi and using them there.

Not to rain on your parade, but the reason these don't exist in the core libraries is they're actually a bit tricky to get right. ;)

We did have them at one point, and then later removed them because they only work with certain arguments, and we didn't want to wrap them in an Eff with an exception or something.

The rules according to MDN:

• toExponential and toFixed throw a RangeError if the digits provided is not between 0 and 20
• toPrecision throws a RangeError if the precision provided is not between 0 and 100
• toString throws a RangeError if the radix provided is not between 2 and 36