时间戳 转化为时间

记录代码块：

    formData(timestamp) {
      const date = new Date(timestamp)
      const Y = date.getFullYear() + '-'
      const M = (date.getMonth() + 1 < 10 ? '0' + (date.getMonth() + 1) : date.getMonth() + 1) + '-'
      const D = date.getDate() + ' '
      const h = date.getHours() < 10 ? '0' + date.getHours() + ':' : date.getHours() + ':'
      const m = date.getMinutes() < 10 ? '0' + date.getMinutes() + ':' : date.getMinutes() + ':'
      const s = date.getSeconds() < 10 ? '0' + date.getSeconds() : date.getSeconds()
      return Y + M + D + h + m + s
    }

timestamp 是 毫秒制，结果为 2017-06-20 17:36:43