javascript-如果数据长度未知，如何获取最后一个循环迭代

Question

I have a loop in JavaScript:

data is just a list of strings. I don't know its length, because data is coming dynamically. This is my loop:

for (var i=1; i < data.length; i++) {
    //how do i catch the last string in the list in loop?
};

it is important that i catch the last object inside loop

is there any this.last() thing which gives me the last iteration?

Answer 1

如果只需要最后一个元素，则无需迭代整个循环。

var last = data[data.length - 1];

Answer 2

To simply capture the last element in an array, use:

var lastItem = data[data.length - 1];

Or to create a new array containing only the last element, use this:

var lastItem = data.slice(-1);

Answer 3

You could check if data[i+1] == undefined inside the loop to find out when you are in the last loop iteration.

When you have no real reason to loop through the array, you can use data[data.length - 1] to access the last entry of the array.