Adding Data.BigInt support.

bower.json

@@ -19,7 +19,8 @@
     "purescript-foreign": "^5.0.0",
     "purescript-generics-rep": "^6.1.1",
     "purescript-foreign-object": "^2.0.3",
-    "purescript-record": "^2.0.1"
+    "purescript-record": "^2.0.1",
+    "purescript-bigints": "^4.0.0"
   },
   "devDependencies": {
     "purescript-assert": "^4.1.0",

package.json

@@ -12,5 +12,8 @@
     "purescript": "^0.13.3",
     "purescript-psa": "^0.7.3",
     "rimraf": "^3.0.0"
+  },
+  "dependencies": {
+    "big-integer": "^1.6.48"
   }
 }

spago.dhall

@@ -5,6 +5,7 @@ You can edit this file as you like.
 { name = "foreign-generic"
 , dependencies =
     [ "assert"
+    , "bigints"
     , "console"
     , "effect"
     , "exceptions"

src/Foreign/Generic/Class.purs

@@ -6,7 +6,9 @@ import Control.Alt ((<|>))
 import Control.Monad.Except (except, mapExcept)
 import Data.Array ((..), zipWith, length)
 import Data.Bifunctor (lmap)
-import Data.Either (Either(..))
+import Data.BigInt (BigInt)
+import Data.BigInt as BigInt
+import Data.Either (Either(..), note)
 import Data.Generic.Rep (Argument(..), Constructor(..), NoArguments(..), NoConstructors, Product(..), Sum(..))
 import Data.Identity (Identity(..))
 import Data.List (List(..), (:))
@@ -204,6 +206,11 @@ instance eitherDecode :: (Decode a, Decode b) => Decode (Either a b) where
       <|>
       (readProp "Right" value >>= (map Right <<< decode))
 
+instance bigIntDecode :: Decode BigInt where
+  decode value = do
+    str <- readString value
+    except $ note (pure (ForeignError ("Expected BigInt"))) $ BigInt.fromString str
+
 -- | The `Encode` class is used to generate encoding functions
 -- | of the form `a -> Foreign` using `generics-rep` deriving.
 -- |
@@ -278,6 +285,9 @@ instance encodeEither :: (Encode a, Encode b) => Encode (Either a b) where
   encode (Left a) = encode $ Object.singleton "Left" a
   encode (Right b) = encode $ Object.singleton "Right" b
 
+instance bigIntEncode :: Encode BigInt where
+  encode = encode <<< BigInt.toString
+
 -- | When deriving `En`/`Decode` instances using `Generic`, we want
 -- | the `Options` object to apply to the outermost record type(s)
 -- | under the data constructors.

test/Main.purs

@@ -4,6 +4,7 @@ import Prelude
 
 import Control.Monad.Except (runExcept)
 import Data.Bifunctor (bimap)
+import Data.BigInt as BigInt
 import Data.Either (Either(..))
 import Data.Generic.Rep (class Generic)
 import Data.Map as Map
@@ -141,6 +142,7 @@ main = do
   testRoundTrip (Object.fromFoldable [Tuple "one" 1, Tuple "two" 2])
   testRoundTrip (Map.fromFoldable [Tuple "one" 1, Tuple "two" 2])
   testRoundTrip [ Left 5, Right "Test" ]
+  testRoundTrip (BigInt.pow (BigInt.fromInt 2) (BigInt.fromInt 60)) -- 2^60. Anything over 2^32 will confuse JavaScript.
   testUnaryConstructorLiteral
   let opts = defaultOptions { fieldTransform = toUpper }
   testGenericRoundTrip opts (RecordTest { foo: 1, bar: "test", baz: 'a' })