24小时时间转为12小时制

            function convertTo12Hour(time24h){
				let [hours, minutes] = time24h.split(':');
				let modifier = '上午';

				if (parseInt(hours, 10) > 12) {
					modifier = '下午';
					hours = (parseInt(hours, 10) - 12).toString();
				}
				if (parseInt(hours, 10) === 12) {
					modifier = '下午';
				}
				if (parseInt(hours, 10) === 0) {
					//hours = '12';//如果这是是12 调用方法时间为00:00 会转换成12:00上午
					hours = '00';
				}

			return `${hours.padStart(2, '0')}:${minutes} ${modifier}`;
				//return `${hours.padStart(2, '0')}点${minutes}`;
			}
		convertTo12Hour('18:30')//'06:30 下午'
		convertTo12Hour('00:30')//'00:30 上午'
		convertTo12Hour('09:00')//'09:30 上午'

12小时时间转为24小时制

function convertTo24Hour(time12h) {
  const [time, modifier] = time12h.split(' ');
  let [hours, minutes] = time.split(':');
  
  if (hours === '12') {
    hours = '00';
  }
  if (modifier === 'PM') {
    hours = parseInt(hours, 10) + 12;
    hours = hours.toString().padStart(2, '0');
  }
  
  return `${hours}:${minutes}`;
}
 
// 示例
console.log(convertTo24Hour('01:30 PM')); // 输出: 13:30
console.log(convertTo24Hour('12:30 AM')); // 输出: 00:30
console.log(convertTo24Hour('11:59 PM')); // 输出: 23:59