Get the last item in an array

To retrieve the last item of an array in JavaScript, we can use the length property of the array to access the last element. Here's a simple example:

javascript
let arr = [10, 20, 30, 40, 50];

To retrieve the last item of this array, we can use the following code:

javascript
let lastItem = arr[arr.length - 1];
console.log(lastItem); // Output: 50

In this example, arr.length returns the length of the array, which is 5. Since array indices start at 0, the index of the last element is arr.length - 1, which is 4. This approach effectively retrieves the last item of the array.

Additionally, if we want this operation to be more flexible and general, we can encapsulate it into a function:

javascript
function getLastItem(array) {
    if (array.length === 0) {
        return undefined; // If the array is empty, return undefined
    }
    return array[array.length - 1];
}

console.log(getLastItem(arr)); // Output: 50
console.log(getLastItem([])); // Output: undefined

This function first checks if the array is empty; if it is, it returns undefined, otherwise it returns the last item of the array. This makes the code more robust and better suited for various input scenarios.