nice challenge that would work in any language

creating-number-range-eloquent-js.js

// As a bonus assignment, modify your range function to take an optional third argument that indicates the “step” value used when building the array. If no step is given, the elements go up by increments of one, corresponding to the old behavior. The function call

// range(1, 10, 2)

// should return

// [1, 3, 5, 7, 9]

// Make sure it also works with negative step values so that

// range(5, 2, -1)

// produces

// [5, 4, 3, 2]

// https://eloquentjavascript.net/Eloquent_JavaScript.pdf

function range(start, end, step) {
    if (step < 0) {
        return stepDown(start, end, step)
    }
    else {
        return stepUp(start, end, step)
    } 
}

function stepUp(start, end, step) {
    arr = [start]
    while (end > start) {
        start = start + step 
        if (end < start) {
            break;
        }
        arr.push(start)
    }
    return arr
}

function stepDown(start, end, step) {
    arr = [start]
    step = step * -1
    while (end < start) {
        start = start - step 
        if (end > start) {
            break;
        }
        arr.push(start)
    }
    return arr
}

console.log(range(5, 2, -1))