Fixing Issue #3731 (#3735)

* Fixing Issue #3731 * Adding entry to the changelog
realm · May 12, 2021 · 269361e · 269361e
1 parent 47b8b52
commit 269361e
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -14,6 +14,7 @@ NOTE: Bump file format version to 21. NO DOWNGRADE PATH IS AVAILABLE.
 * <How to hit and notice issue? what was the impact?> ([#????](https://github.com/realm/realm-js/issues/????), since v?.?.?)
 * Set didn't export `objectType` to Realm.schema when it contained scalar types.
 * Fixed the naming of `url` (now `baseUrl`) property on an app config to match the TypeScript declaration and other SDKs. ([#3612](https://github.com/realm/realm-js/issues/3612))
+* Add explicity support for Nullable/Undefined values for the Mixed type. ([#3731](https://github.com/realm/realm-js/issues/3731))
 
 ### Compatibility
 * MongoDB Realm Cloud.

diff --git a/src/common/type_deduction.hpp b/src/common/type_deduction.hpp
@@ -75,6 +75,14 @@ class GenericTypeDeductionImpl {
         return realm_to_js_map[value];
     }
 
+    template <typename MixedValue>
+    types::Type from(MixedValue mixed) {
+        if(mixed.is_null()) return types::Type::Null;
+
+        int realm_type = static_cast<int>(mixed.get_type());
+        return static_cast<types::Type>(realm_type);
+    }
+
     types::Type from(DataType data_type) {
         int realm_type = static_cast<int>(data_type);
         return static_cast<types::Type>(realm_type);

diff --git a/src/js_mixed.hpp b/src/js_mixed.hpp
@@ -105,6 +105,17 @@ class MixedUUID : public MixedWrapper<Context, Value> {
     }
 };
 
+template <typename Context, typename Value, typename Utils>
+class MixedNullable : public MixedWrapper<Context, Value> {
+    Mixed wrap(Context context, Value const &value) {
+        return Mixed();
+    }
+
+    Value unwrap(Context context, Mixed mixed) {
+        return Utils::from_null(context);
+    }
+};
+
 template <typename Context, typename Value, typename Utils>
 class MixedBinary : public MixedWrapper<Context, Value> {
    private:
@@ -166,6 +177,8 @@ class TypeMixed {
         {types::UUID, new MixedUUID<Context, Value, Utils>},
         {types::Binary, new MixedBinary<Context, Value, Utils>},
         {types::Timestamp, new MixedTimeStamp<Context, Value, Utils>},
+        {types::Null, new MixedNullable<Context, Value, Utils>},
+        {types::Undefined, new MixedNullable<Context, Value, Utils>},
     };
 
     TypeMixed() {}
@@ -186,7 +199,7 @@ class TypeMixed {
 
     Value wrap(Context context, Mixed mixed) {
         auto type_deduction = TypeDeduction::get_instance();
-        auto rjs_type = type_deduction.from(mixed.get_type());
+        auto rjs_type = type_deduction.from(mixed);
         auto strategy = strategies[rjs_type];
 
         if (strategy == nullptr) {

diff --git a/tests/js/mixed-tests.js b/tests/js/mixed-tests.js
@@ -23,7 +23,6 @@ const TestCase = require('./asserts');
 
 const {Decimal128, ObjectId, UUID} = Realm.BSON;
 
-
 const SingleSchema = {
     name: 'mixed',
     properties: {
@@ -173,6 +172,34 @@ module.exports = {
             () => realm.write(()=> realm.create(SingleSchema.name, { a: Object.create({}) }  ) ),
             new Error('Only Realm instances are supported.') )
     },
+
+    testMixedEmptyValues() {
+        const MixedNullableSchema = {
+            name: 'mixed',
+            properties: {
+                nullable: 'mixed',
+                nullable_list: 'mixed[]'
+            }
+        }
+
+        let realm = new Realm({schema: [MixedNullableSchema]});
+        realm.write(()=> realm.create(MixedNullableSchema.name, { nullable: undefined }  ) )
+
+        let value = realm.objects(MixedNullableSchema.name)[0]
+        realm.write(()=> value.nullable = null )
+        realm.write(()=> value.nullable = undefined )
+
+        realm.write(() => {
+            value.nullable_list = [6, null, undefined, null, 5]
+        });
+
+        TestCase.assertEqual(value.nullable_list[0],  6, 'Should be equal 6');
+        TestCase.assertEqual(value.nullable_list[1],  null, 'Should be equal null');
+        TestCase.assertEqual(value.nullable_list[2],  null, 'Should be equal null');
+        TestCase.assertEqual(value.nullable_list[3],  null, 'Should be equal null');
+        TestCase.assertEqual(value.nullable_list[4],  5, 'Should be equal 5');
+    },
+
 }