used an if else statement

The way you solved it works as expected, however a few minor changes might improve it. Such as using an if-elseif-else check instead of individual if checks.

function arrayCounter(array) {
    if(typeof  array === 'undefined') {
        return 0;
    } else if(typeof array === 'number') {
        return 0;
    } else if(typeof array === 'string') {
        return 0;
    } else {
        return array.length;
    }
}

This actually won't matter much though, since if it passes any of the checks it will immediately return either way, so I doubt there is much of a performance difference.

Another alternative is to consolidate your type checking into one if statement instead of multiple.

function arrayCounter(array) {
    if(typeof  array === 'undefined' || typeof array === 'number' || typeof array === 'string') {
        return 0;
    } else {
        return array.length;
    }
}

This is a bit more terse, and probably a more standard approach.

Finally, there is also another function not mentioned in that video called instanceof which works similar to typeof only it will compare actual types instead of casting the type to a string.

function arrayCounter(array) {
    if(array instanceof Array) {
        return array.length;
    } else {
        return 0;
    }
}