fix(reactivity): readonly+reactive collection should also expose readonly+reactive values

fix #1772

packages/reactivity/__tests__/readonly.spec.ts

@@ -205,6 +205,22 @@ describe('reactivity/readonly', () => {
         ).toHaveBeenWarned()
       })
 
+      // #1772
+      test('readonly + reactive should make get() value also readonly + reactive', () => {
+        const map = reactive(new Collection())
+        const roMap = readonly(map)
+        const key = {}
+        map.set(key, {})
+
+        const item = map.get(key)
+        expect(isReactive(item)).toBe(true)
+        expect(isReadonly(item)).toBe(false)
+
+        const roItem = roMap.get(key)
+        expect(isReactive(roItem)).toBe(true)
+        expect(isReadonly(roItem)).toBe(true)
+      })
+
       if (Collection === Map) {
         test('should retrieve readonly values on iteration', () => {
           const key1 = {}
@@ -223,6 +239,28 @@ describe('reactivity/readonly', () => {
             expect(isReadonly(value)).toBe(true)
           }
         })
+
+        test('should retrieve reactive + readonly values on iteration', () => {
+          const key1 = {}
+          const key2 = {}
+          const original = reactive(new Collection([[key1, {}], [key2, {}]]))
+          const wrapped: any = readonly(original)
+          expect(wrapped.size).toBe(2)
+          for (const [key, value] of wrapped) {
+            expect(isReadonly(key)).toBe(true)
+            expect(isReadonly(value)).toBe(true)
+            expect(isReactive(key)).toBe(true)
+            expect(isReactive(value)).toBe(true)
+          }
+          wrapped.forEach((value: any) => {
+            expect(isReadonly(value)).toBe(true)
+            expect(isReactive(value)).toBe(true)
+          })
+          for (const value of wrapped.values()) {
+            expect(isReadonly(value)).toBe(true)
+            expect(isReactive(value)).toBe(true)
+          }
+        })
       }
     })
   })