diff --git a/js/src/JS/Date.idr b/js/src/JS/Date.idr
index 2ac366a..9bd1fd2 100644
--- a/js/src/JS/Date.idr
+++ b/js/src/JS/Date.idr
@@ -8,8 +8,8 @@ import Data.String
 public export
 data JSDate : Type where [external]
 
-%foreign "javascript:lambda:(w) => new Date(w)"
-prim__date : Bits32 -> JSDate
+%foreign "javascript:lambda:(w) => new Date(Number(w))"
+prim__date : Bits64 -> JSDate
 
 %foreign "javascript:lambda:(w) => new Date(w)"
 prim__stringDate : String -> JSDate
@@ -20,20 +20,20 @@ prim__toLocaleDateString : JSDate -> String
 %foreign "javascript:lambda:(w) => w.toLocaleTimeString()"
 prim__toLocaleTimeString : JSDate -> String
 
-%foreign "javascript:lambda:(d) => d.getTime()"
-prim__getTime : JSDate -> Bits32
+%foreign "javascript:lambda:(d) => BigInt(d.getTime())"
+prim__getTime : JSDate -> Bits64
 
-%foreign "javascript:lambda:(d) => d.getFullYear()"
-prim__getFullYear : JSDate -> Bits32
+%foreign "javascript:lambda:(d) => BigInt(d.getFullYear())"
+prim__getFullYear : JSDate -> Bits64
 
-%foreign "javascript:lambda:(d) => d.getMonth()"
-prim__getMonth : JSDate -> Bits32
+%foreign "javascript:lambda:(d) => BigInt(d.getMonth())"
+prim__getMonth : JSDate -> Bits64
 
-%foreign "javascript:lambda:(d) => d.getDate()"
-prim__getDate : JSDate -> Bits32
+%foreign "javascript:lambda:(d) => BigInt(d.getDate())"
+prim__getDate : JSDate -> Bits64
 
 export %inline
-Cast Bits32 JSDate where cast = prim__date
+Cast Bits64 JSDate where cast = prim__date
 
 export %inline
 Cast String JSDate where cast = prim__stringDate
@@ -47,27 +47,27 @@ toLocaleTimeString : JSDate -> String
 toLocaleTimeString = prim__toLocaleTimeString
 
 export %inline
-getTime : JSDate -> Bits32
+getTime : JSDate -> Bits64
 getTime = prim__getTime
 
 export %inline
-getFullYear : JSDate -> Bits32
+getFullYear : JSDate -> Bits64
 getFullYear = prim__getFullYear
 
 export %inline
-getMonth : JSDate -> Bits32
+getMonth : JSDate -> Bits64
 getMonth = prim__getMonth
 
 export %inline
-getDate : JSDate -> Bits32
+getDate : JSDate -> Bits64
 getDate = prim__getDate
 
-pad2 : Bits32 -> String
+pad2 : Bits64 -> String
 pad2 v = padLeft 2 '0' (show v)
 
 ||| Prints a date in the format "yyyy-mm-dd"
 export
-dateString : Bits32 -> String
+dateString : Bits64 -> String
 dateString ts =
   let d := cast {to = JSDate} ts
    in "\{show $ getFullYear d}-\{pad2 $ getMonth d + 1}-\{pad2 $ getDate d}"