前端获取当前日期---------------年月日//时分秒

当前时间，先分组匹配，以数组下标索引匹配定义的汉字进行替换

处理日期方法

/* 日期格式化 */
const formatTime = function formatTime(time, template) {
    if (typeof time !== "string") {
        time = new Date().toLocaleString('zh-CN', { hour12: false });
    }
    if (typeof template !== "string") {
        template = "{0}年{1}月{2}日 {3}:{4}:{5}";
    }
    let arr = [];
    if (/^\d{8}$/.test(time)) {
        let [, $1, $2, $3] = /^(\d{4})(\d{2})(\d{2})$/.exec(time);
        arr.push($1, $2, $3);
    } else {
        arr = time.match(/\d+/g);
    }
    return template.replace(/\{(\d+)\}/g, (_, $1) => {
        let item = arr[$1] || "00";
        if (item.length < 2) item = "0" + item;
        return item;
 

导入定义的工具方法

import _ from '../assets/utils'

import React, { useMemo, useEffect } from 'react'
import timg from '../assets/images/timg.jpg'
import './HomeHead.less'
import { connect } from 'react-redux'
import action from '../store/action'
import { useNavigate } from 'react-router-dom'

const HomeHead = function HomeHead(props) {
  const navigate = useNavigate()

  /* 计算时间中的月和日 */
  let { today, info, queryUserInfoAsync } = props
  let time = useMemo(() => {
    //通过正则取数字
    let [, year, month, day] = today.match(/^\d{0}(\d{4})(\d{2})(\d{2})$/),
      area = [
        '零','一', '二', '三', '四','五','六','七','八','九','十','十一','十二',
      ]
    return {
      year: +year + '年',
      month: area[+month] + '月',
      day: +day + '日',
    }
  }, [today])

  // 第一次渲染完:如果info中没有信息,我们尝试派发一次,获取到登陆者信息
  useEffect(() => {
    if (!info) {
      queryUserInfoAsync()
    }
  }, [])

  return (
    <header className="home-head-box">
      {/* 时间，标题 */}
      <div className="info">
        <div className="time">
          <span>{time.year}</span>
          <div className="month_day">
            <span>{time.month}</span>
            <span>{time.day}</span>
          </div>
        </div>
        <h2 className="title">知乎日报</h2>
      </div>
      {/* {头像} */}
      <div
        className="picture"
        onClick={() => {
          navigate('/personal')
        }}
      >
        <img src={info ? info.pic : timg} alt="" />
      </div>
    </header>
  )
}
export default connect((state) => state.base, action.base)(HomeHead)

截取获取当前时分秒

new Date().toLocaleString().split('/').join('').slice(-8)
'16:30:09'

截取掉冒号,获取当前时分秒

new Date().toLocaleString().split('/').join('').slice(-8).split(':').join('')

//'163037'

let time = new Date().toLocaleString().split('/').join('').slice(-8).split(':').join('')
 
console.log(time.match(/^\d{0}(\d{2})(\d{2})(\d{2})$/));

使用数组解构接收，

 
 
let time = new Date().toLocaleString().split('/').join('').slice(-8).split(':').join('')
let [,hour,minute,second]= time.match(/^\d{0}(\d{2})(\d{2})(\d{2})$/)
console.log(hour,minute,second);

截取掉/ （斜杠）获取当前年月日

new Date().toLocaleString().split('/').join('').slice(0,8)
//'20231212 '

new Date().toLocaleString().split('/').join('').slice(0,8).match(/^\d{0}(\d{4})(\d{2})(\d{2})$/)

使用数组解构接收，

   let time = new Date().toLocaleString().split('/').join('').slice(0,8).match(/^\d{0}(\d{4})(\d{2})(\d{2})$/)
      let [, year, month, day] = time
      
      console.log(year, month, day);

//不需要的直接 ， 为空就行

注意：获取的是string类型，如果需要数字类型，使用+号转义