实现instanceof方法

function instanceof_myself(leftValue,rightValue) {
    let rightPrototype = rightValue.prototype; //获取右侧构造函数对应的原型
    let leftProto=leftValue.__proto__;//获取左侧实例对应的原型
    while(true) {
        if (leftProto === null) {
            return false;
        } else if (leftProto === rightPrototype) {
            return true;
        } 
        leftProto=leftProto.__proto__;
    }
}