fix: support prop type checking for primitive wrapper objects (#6450)

close #6447

src/core/util/props.js

@@ -145,7 +145,12 @@ function assertType (value: any, type: Function): {
   let valid
   const expectedType = getType(type)
   if (simpleCheckRE.test(expectedType)) {
-    valid = typeof value === expectedType.toLowerCase()
+    const t = typeof value
+    valid = t === expectedType.toLowerCase()
+    // for primitive wrapper objects
+    if (!valid && t === 'object') {
+      valid = value instanceof type
+    }
   } else if (expectedType === 'Object') {
     valid = isPlainObject(value)
   } else if (expectedType === 'Array') {

test/unit/features/options/props.spec.js

@@ -206,6 +206,17 @@ describe('Options props', () => {
       expect('Expected Array').toHaveBeenWarned()
     })
 
+    it('primitive wrapper objects', () => {
+      /* eslint-disable no-new-wrappers */
+      makeInstance(new String('s'), String)
+      expect(console.error.calls.count()).toBe(0)
+      makeInstance(new Number(1), Number)
+      expect(console.error.calls.count()).toBe(0)
+      makeInstance(new Boolean(true), Boolean)
+      expect(console.error.calls.count()).toBe(0)
+      /* eslint-enable no-new-wrappers */
+    })
+
     if (hasSymbol) {
       it('symbol', () => {
         makeInstance(Symbol('foo'), Symbol)