/**
 * scroller 滚动条元素
 * to 滚动到位置
 * duration 滚动时间
 */
function scrollLeftTo (scroller, to, duration) {
  let rafId
  let count = 0
  const from = scroller.scrollLeft
  const frames = duration === 0 ? 1 : Math.round((duration * 1000) / 16)

  function cancel () {
    cancelAnimationFrame(rafId)
  }

  function animate () {
    scroller.scrollLeft += (to - from) / frames

    if (++count < frames) {
      rafId = requestAnimationFrame(animate)
    }
  }

  animate()

  return cancel
}

应用：

   let activeTab = this.$el.querySelector('.is-active')
   if (activeTab) {
        let navScroll = this.$refs.navScroll
        // 计算滚动位置
        const to = activeTab.offsetLeft - (navScroll.offsetWidth - activeTab.offsetWidth) / 2
        this.cancelScrollLeftToRaf && this.cancelScrollLeftToRaf()
        this.cancelScrollLeftToRaf = scrollLeftTo(navScroll, to, 0.3)
      }

效果：