How do I convert a list of chars to a string in purescript

I agree with your edit. Data.String.fromCharArray <<< Data.List.fromList sounds pretty decent to me. fromCharArray is implemented in native JS with array.join("").

Update: fromList is deprecated now - use toUnfoldable instead

[Updated Jan 2021]

In PureScript 0.13.8:

import Prelude 

> import Data.Array (toUnfoldable)
> import Data.String.CodeUnits (fromCharArray)
> fromListChars = fromCharArray <<< toUnfoldable
> fromListChars ['2', '0', '2', '1']
"2021"

> fromListChars []
""