Add tests for purescript number and parser utilities

1 files changed, 22 insertions, 0 deletions

diff --git a/js/src/Number.purs b/js/src/Number.purs
new file mode 100644
index 0000000..0403f19
--- /dev/null
+++ b/js/src/Number.purs
@@ -0,0 +1,22 @@
+module Number
+  ( format
+  , roundAt
+  ) where
+
+import Data.Int (round, toNumber, pow) as Int
+import Data.String (Pattern(..), Replacement(..))
+import Data.String (replace) as String
+import Math (round) as Math
+import Prelude
+
+format :: Number -> String
+format number =
+  if Math.round number == number then
+    show (Int.round number)
+  else
+    String.replace (Pattern ".") (Replacement ",") (show (roundAt 1 number))
+
+roundAt :: Int -> Number -> Number
+roundAt at n =
+  let exp = Int.toNumber (Int.pow 10 at)
+  in  Math.round (n * exp) / exp