vue监听按下ctrl或shift

// 在页面钩子 mounted() 处调用此函数，增加按键监听事件

watchKeyEvent () {
  const setKeyStatus = (keyCode, status) => {
    switch (keyCode) {
      case 16:
        if (this.onShfit === status) return
        console.log('shif', status ? '按下' : '抬起')
        this.onShfit = status
        break
      case 17:
        if (this.onCtrl === status) return
        console.log('ctrl', status ? '按下' : '抬起')
        this.onCtrl = status
        break
    }
  }
  document.onkeydown = (e) => {
    setKeyStatus(e.keyCode, true)
  }
  document.onkeyup = (e) => {
    setKeyStatus(e.keyCode, false)
  }
}

效果（自己试试）