thi-ng/umbrella

export function range(): IterableIterator<number>;
export function range(to: number): IterableIterator<number>;
export function range(from: number, to: number): IterableIterator<number>;
export function range(
    from: number,
    to: number,
    step: number
): IterableIterator<number>;
export function* range(from?: number, to?: number, step?: number) {
    if (from === undefined) {
        from = 0;
        to = Infinity;
    } else if (to === undefined) {
        to = from;
        from = 0;
    }
    step = step === undefined ? (from < to ? 1 : -1) : step;
    if (step > 0) {
        while (from < to) {
            yield from;
            from += step;
        }
    } else if (step < 0) {
        while (from > to) {
            yield from;
            from += step;
        }
    }
}