splicemethod.js

function maxOf(arr) {
    // base case: only one element left in arr
    if (arr.length === 1) {
        return arr[0]
    }
    // compare first two elements and remove smaller one
    if (arr[1] > arr[0]) {
        arr.splice(0, 1) // remove arr[0]
    } else {
        arr.splice(1, 1) // remove arr[1]
    }
    return maxOf(arr)
}