export function increment(num: number, length: number): number {
  return (num + 1) % length
}

export function decrement(num: number, length: number): number {
  return (num + length - 1) % length
}

export function expand(num: number): string {
  return ('0000' + num.toString()).slice(-4)
}

export function isMobile(): boolean {
  return window.matchMedia('(hover: none)').matches
}