step > 0 ? end >= start : end <= start function in javascript meaning code example

Example 1: javascript create range with a loop

function createRange(min, max) {
    var range = [];
    for (let i = min; i <= max; i++) {
        range.push(i);
    }
    return range;
}

createRange(1, 5)
// => [1, 2, 3, 4, 5]

Example 2: range command in JS

function range(start, end) {
    return (new Array(end - start + 1)).fill(undefined).map((_, i) => i + start);
}