1[...Array(5).keys()];
2 => [0, 1, 2, 3, 4]

1function range(start, end) {
2	/* generate a range : [start, start+1, ..., end-1, end] */
3	var len = end - start + 1;
4	var a = new Array(len);
5	for (let i = 0; i < len; i++) a[i] = start + i;
6	return a;
7}

1
2function range(start, end, interval = 0) {
3        let arr = [];
4        interval = interval > 0 ? interval-1 : 0
5        for (let i = start; i < end; i++) {
6             arr.push(i)
7             i+=interval;
8        }
9        return arr
10    }
11// example range(0 , 100 , 5)