hasOwnProperty与in的区别

Person.prototype.lastName = "Deng";

function Person() {
}

var person = new Person();
person.age = 12;

if (person.hasOwnProperty(‘lastName‘)) {
    //找不到不执行
    console.log(person.lastName)
}

if (person.hasOwnProperty(‘age‘)) {
    //能找到会输出12
    console.log(person.age)
}

console.log(‘lastName‘in person)
//返回true