js中的instanceof是判断依据是对象的__proto__是否等于方法/类的prototype，若否则沿着原型链向上寻找，直到为null时返回false，大体实现如下

function checkIsInstanceOf(obj,Class){
        let proto=Object.getPrototypeOf(obj);
        if(proto === Class.prototype){
            return true;
        }
        while(proto != null){
            proto=Object.getPrototypeOf(proto);
            if(proto === Class.prototype){
                return true;
            }
        }
        return false;
    }

测试如下

class Test1 extends Array{

    }
    class Test2 extends Test1{

    }
    class Test3 extends Test2{

    }

    const t=new Test3();
    console.log(t instanceof Array,t instanceof Test3,t instanceof Test2,t instanceof Test1,t instanceof Date);

console.log(checkIsInstanceOf(t,Test3),checkIsInstanceOf(t,Test2),checkIsInstanceOf(t,Test1),
                checkIsInstanceOf(t,Array),checkIsInstanceOf(t,Date));