Switch from setImmediate to setTimeout to support Next 9.3. (#62)

* Switch from setImmediate to setTimeout to support Next 9.3.

* bumped version

* Fix failing tests.

Author: markbrocato

package.json

@@ -1,6 +1,6 @@
 {
   "name": "react-storefront",
-  "version": "7.9.1",
+  "version": "7.9.2",
   "description": "Build and deploy e-commerce progressive web apps (PWAs) in record time.",
   "module": "./index.js",
   "license": "Apache-2.0",

src/nav/NavTab.js

@@ -86,10 +86,10 @@ function NavTab({ classes, href, as, prefetch, children, ...props }) {
     setAnchorEl(event.currentTarget)
   }, [])
 
-  // We use setImmediate here to delay the tab and menu exit events give time for the user to enter
+  // We use setTimeout here to delay the tab and menu exit events give time for the user to enter
   // the tab or menu so that the menu doesn't flash when the user is transitioning between tab and menu.
-  const hideMenu = useCallback(() => setImmediate(() => setOverTab(false)), [])
-  const leaveMenu = useCallback(() => setImmediate(() => setOverMenu(false)), [])
+  const hideMenu = useCallback(() => setTimeout(() => setOverTab(false)), [])
+  const leaveMenu = useCallback(() => setTimeout(() => setOverMenu(false)), [])
   const enterMenu = useCallback(() => setOverMenu(true), [])
   const menuItemBlurPending = useRef(false)
 
@@ -114,7 +114,7 @@ function NavTab({ classes, href, as, prefetch, children, ...props }) {
   const handleMenuItemBlur = useCallback(() => {
     menuItemBlurPending.current = true
 
-    setImmediate(() => {
+    setTimeout(() => {
       if (menuItemBlurPending.current) {
         setFocused(false)
       }

test/nav/NavTab.test.js

@@ -15,9 +15,13 @@ describe('NavTab', () => {
     document.body.removeChild(root)
     root = null
     wrapper.unmount()
+    jest.clearAllMocks()
   })
 
   beforeEach(() => {
+    // setImmediate seems to be much more stable than set timeout for tests, so we us it here to prevent intermittant failures
+    jest.spyOn(global, 'setTimeout').mockImplementation(setImmediate)
+
     document.createRange = () => ({
       setStart: () => {},
       setEnd: () => {},