Fix #8

Author: i-am-the-slime

spago.dhall

@@ -19,6 +19,7 @@
   , "maybe"
   , "newtype"
   , "nullable"
+  , "numbers"
   , "ordered-collections"
   , "partial"
   , "prelude"

src/Yoga/JSON.purs

@@ -41,7 +41,7 @@ import Data.Array.NonEmpty (NonEmptyArray, fromArray, toArray)
 import Data.Bifunctor (lmap)
 import Data.BigInt (BigInt)
 import Data.BigInt as BigInt
-import Data.Either (Either, hush, note)
+import Data.Either (Either(..), hush, note)
 import Data.FoldableWithIndex (foldrWithIndex)
 import Data.Identity (Identity(..))
 import Data.Int as Int
@@ -51,6 +51,7 @@ import Data.Map as Map
 import Data.Maybe (Maybe(..), fromMaybe, fromMaybe', maybe)
 import Data.Newtype (class Newtype)
 import Data.Nullable (Nullable, toMaybe, toNullable)
+import Data.Number as Number
 import Data.Symbol (class IsSymbol, reflectSymbol)
 import Data.Traversable (sequence, traverse)
 import Data.TraversableWithIndex (traverseWithIndex)
@@ -185,18 +186,25 @@ readBigInt ∷
 readBigInt = unsafeReadTagged "BigInt"
 
 instance ReadForeign BigInt where
-  readImpl fValue = tryInt fValue <|> readBigInt fValue <|> tryString fValue
+  readImpl fValue = tryInt fValue <|> tryNumber fValue <|> readBigInt fValue <|> tryString fValue
     where
     tryInt f = readInt f <#> BigInt.fromInt
+    tryNumber f = do
+      num <- readNumber f
+      if Number.round num == num then
+        BigInt.fromNumber num
+          # note (err $ "Cannot convert Number " <> show num <> " to BigInt")
+          # except
+        else
+          (Left $ err $ "Cannot convert decimal Number " <> show num <> " to BigInt")
+            # except
     tryString f = do
       bi ← readString f
       BigInt.fromString bi
-        # note
-            ( singleton $ ForeignError $ "String " <> bi <>
-                " could not be converted to BigInt"
-            )
+        # note ( err $ "Cannot convert String " <> bi <> " to BigInt")
         # except
-        
+    err = pure <<< ForeignError
+
 instance ReadForeign String where
   readImpl = readString
 

test/BasicsSpec.purs

@@ -54,9 +54,9 @@ spec = describe "En- and decoding" $ do
       $ roundtrips (Map.fromFoldable [(Inty 4 /\ "B"),(Inty 8 /\ "D")])
     it "roundtrips BigInt" do
       let
-        inputStr = """{ "number":1, "big": 18014398509481982, "smallBig": 10 }"""
-        expected = """{"smallBig":"10","number":1,"big":"18014398509481982"}"""
-        parsed ∷ _ ({ number ∷ Int, big ∷ BigInt, smallBig ∷ BigInt })
+        inputStr = """{ "number":1, "big": 18014398509481982, "mediumBig": 1652955871799, "smallBig": 10 }"""
+        expected = """{"smallBig":"10","number":1,"mediumBig":"1652955871799","big":"18014398509481982"}"""
+        parsed ∷ _ ({ number ∷ Int, mediumBig :: BigInt, big ∷ BigInt, smallBig ∷ BigInt })
         parsed = readJSON inputStr
         stringified = parsed <#> writeJSON
       stringified `shouldEqual` (Right expected)
@@ -65,7 +65,7 @@ spec = describe "En- and decoding" $ do
     --   let
     --     smallBig = BigInt.fromInt 10
     --     big = unsafePartial $ fromJust $ BigInt.fromString "18014398509481982"
-        
+
     --     expected = { big, smallBig }
     --     json = spy "json" $ writeJSON expected
 

test/GenericsSpec.purs

@@ -46,6 +46,7 @@ spec = describe "Generics" $ do
         writeJSON (ATaggedInt 1) `shouldEqual` """{"type":"ATaggedInt","value":1}"""
         writeJSON (ATaggedString "Abc") `shouldEqual` """{"type":"ATaggedString","value":"Abc"}"""
 
+
     describe "data HalfEnum = NotEnum Int | IsEnum" do
       it "roundtrips" do
         roundtrips (NotEnum 1)