constructor 属性返回对创建此对象的数组函数的引用。
例如：const obj = {a: 1}
console.log(obj.constructor) // function Object() { [native code] }
console.log(obj.constructor === Object) true
console.log(obj.constructor === 'object') false
console.log(typeof obj) // object
console.log(typeof obj === 'object') true
console.log(typeof obj === Object) false