test: reactive proto

packages/reactivity/__tests__/reactive.spec.ts

@@ -26,6 +26,20 @@ describe('reactivity/reactive', () => {
     expect(Object.keys(observed)).toEqual(['foo'])
   })
 
+  test('proto', () => {
+    const obj = {}
+    const reactiveObj = reactive(obj)
+    expect(isReactive(reactiveObj)).toBe(true)
+    // read prop of reactiveObject will cause reactiveObj[prop] to be reactive
+    // @ts-ignore
+    const prototype = reactiveObj['__proto__']
+    const otherObj = { data: ['a'] }
+    expect(isReactive(otherObj)).toBe(false)
+    const reactiveOther = reactive(otherObj)
+    expect(isReactive(reactiveOther)).toBe(true)
+    expect(reactiveOther.data[0]).toBe('a')
+  })
+
   test('nested reactives', () => {
     const original = {
       nested: {

packages/reactivity/src/reactive.ts

@@ -1,4 +1,4 @@
-import { isObject, toRawType, def } from '@vue/shared'
+import { isObject, toRawType, def, hasOwn } from '@vue/shared'
 import {
   mutableHandlers,
   readonlyHandlers,
@@ -116,18 +116,19 @@ function createReactiveObject(
     return target
   }
   // target already has corresponding Proxy
-  let observed = isReadonly ? target.__v_readonly : target.__v_reactive
-  if (observed !== void 0) {
-    return observed
+  if (
+    hasOwn(target, isReadonly ? ReactiveFlags.readonly : ReactiveFlags.reactive)
+  ) {
+    return isReadonly ? target.__v_readonly : target.__v_reactive
   }
   // only a whitelist of value types can be observed.
   if (!canObserve(target)) {
     return target
   }
-  const handlers = collectionTypes.has(target.constructor)
-    ? collectionHandlers
-    : baseHandlers
-  observed = new Proxy(target, handlers)
+  const observed = new Proxy(
+    target,
+    collectionTypes.has(target.constructor) ? collectionHandlers : baseHandlers
+  )
   def(
     target,
     isReadonly ? ReactiveFlags.readonly : ReactiveFlags.reactive,