js 随机生成大小写字母数字16位数

          const length = 16
          const characters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'
          let result = ''
          for (let i = 0; i < length; i++) {
             result += characters.charAt(Math.floor(Math.random() * characters.length))
                    }