JS怎么生成系统时间字符串

可以使用JavaScript的Date对象获取当前系统时间，再将时间格式化成字符串。具体实现如下：

const now = new Date();
const year = now.getFullYear();
const month = now.getMonth() + 1;
const day = now.getDate();
const hour = now.getHours();
const minute = now.getMinutes();
const second = now.getSeconds();

// 将数字补齐两位数
function padZero(num) {
  return num < 10 ? '0' + num : num;
}

const timeString = `${year}-${padZero(month)}-${padZero(day)} ${padZero(hour)}:${padZero(minute)}:${padZero(second)}`;
console.log(timeString);

输出结果类似于：`2021-07-19 11:27:30`。