以数组为参数的JavaScript函数

Question

I am trying to create a JavaScript function that takes an array as a parameter and returns the first item in the array. This should work for an array of any size. Here is what I have so far, it appears to work just fine in the console but my instructor says there's a better way to do this:

var array = [];

function numbaOne(array) {
    for (var i = 0; i < array.length; i++) {
        console.log(array[0])
    };
}

Any help would be appreciated. I've read about data structures and arrays but can't figure out how to simplify or make this better.

Answer 1

What you are doing is looping over the array and printing out the first item each time. You just want:

var array = [...];

function numbaOne(array) {
    console.log(array[0]); // Print out the first value of the array
    return array[0]; // Return the first value of the array
}

There is one edge case here. If the array is empty, then the function will fail because array[0] will be undefined . So, a more complete version might be:

var array = [...];

function numbaOne(array) {
    if(array.length > 0) { // Check if there is anything in the array
        console.log(array[0]);
        return array[0];
    } else { // If there isn't, let's return something "bad"
        console.log("The array is empty!");
        return undefined;
    }
}