vue 监听全局键盘热键

	document.onkeydown = e => {
    
    
		// const key = window.event.keyCode
		// 避免onkeydown一直监听
        if (e.repeat) {
    
    
          return
        }
        if (e.code === 'ArrowUp') {
    
     
          this.checkUp()
        }
        if (e.code === 'ArrowDown') {
    
    
          this.checkDown()
        }
        if (e.code === 'KeyS' && e.ctrlKey === true) {
    
    
          this.saveNext()
        }
        if (e.code === 'KeyD' && e.ctrlKey === true) {
    
    
          this.deleteNext()
        }
      }