Add initial primitive dispatcher tests

Author: kitten

src/internals/__tests__/dispatcher.test.js

@@ -0,0 +1,14 @@
+import { Dispatcher } from '../dispatcher'
+
+describe('useEffect', () => {
+  it('is a noop', () => {
+    expect(Dispatcher.useEffect).not.toThrow()
+  })
+})
+
+describe('useCallback', () => {
+  it('is an identity function', () => {
+    const fn = () => {}
+    expect(Dispatcher.useCallback(fn)).toBe(fn)
+  })
+})

src/internals/dispatcher.js

@@ -231,9 +231,6 @@ function useRef<T>(initialValue: T): { current: T } {
   const previousRef = workInProgressHook.memoizedState
   if (previousRef === null) {
     const ref = { current: initialValue }
-    if (__DEV__) {
-      Object.seal(ref)
-    }
     workInProgressHook.memoizedState = ref
     return ref
   } else {