text: const _CONFIG = {
    forward: 15,
    backward: 15,
  }
  
  export default function seek(el, shisa) {
    el.classList.add('shisa-seek')
    const attr = Array.from(el.attributes).find(v => {
      return /data-seek-/.test(v.name)
    })
    if (!attr) return
    const direction = attr.name.slice(10)
    let step = attr.value
  
    if (direction === 'forward' || direction === 'backward') {
      step = step && !isNaN(+step) ? +step : _CONFIG[direction]
      attr.value = step
      step = direction === 'forward' ? step : - step
      el.addEventListener('click', () => {
        shisa.seek(shisa.currentTime + step)
      })
    }
  }
  