How JS determines whether an object belongs to a class

The class itself points to the constructor , The data type of a class is a function

• instanceOf： Judge the function of the constructor prototype Whether the attribute appears anywhere in the prototype chain of the object

        function Person(name){
    
            this.name=name
        }
        var obj=new Person(' Zhang San ')
        var obj1={
    }    
        console.log(obj instanceof Person);//true
        console.log(obj1 instanceof Person);//false

• Of the properties of an object constructor To judge , Constructor pointing to the object

        function Person(name) {
    
            this.name = name
        }
        var obj = new Person(' Zhang San ')
        console.log(obj.__proto__.constructor);
        obj.__proto__.constructor=Array
        console.log(obj.__proto__.constructor);