fix(shallow): undefined value (#3205)

* add failing test

* check with .has

Author: dai-shi

src/vanilla/shallow.ts

@@ -19,7 +19,7 @@ const compareEntries = (
     return false
   }
   for (const [key, value] of mapA) {
-    if (!Object.is(value, mapB.get(key))) {
+    if (!mapB.has(key) || !Object.is(value, mapB.get(key))) {
       return false
     }
   }

tests/vanilla/shallow.test.tsx

@@ -170,6 +170,10 @@ describe('shallow', () => {
     const arr = [1, 2]
     expect(shallow([arr, 1], [arr, 1])).toBe(true)
   })
+
+  it('should work with undefined (#3204)', () => {
+    expect(shallow({ a: undefined }, { b: 1 })).toBe(false)
+  })
 })
 
 describe('mixed cases', () => {