数组和for循环的构造函数显示错误

Question

我的代码如下

// Our Person constructor
function Person (name, age) {
this.name = name;
this.age = age;
}
// Now we can make an array of people
var family= new Array();
family[0]= new Person("alice", 40);
family[1]= new Person("bob", 42);
family[2]= new Person("michelle", 8);
family[3]= new Person("timmy", 6);

// loop through our new array
for(var i = 0; i <= family.length; i++) {
console.log("My name is " + family[i].name);
}

唐，不是为什么，但它显示如下所示的错误

My name is alice
My name is bob
My name is michelle
My name is timmy

---
We're running a test below to make sure your code works.
My name is aliceMy name is bobMy name is michelleMy name is timmy
TypeError: family[i] is undefined

我无法纠正这个问题。请帮我解决。

Answer 1

i <= family.length

应该是

i < family.length

因为，数组indeces从零开始。因此，当您达到i的最大值时，数组中不存在元素，因此undefined