项目笔记

项目开发笔记

获取当前项目应用上下文（前后端不分离）

function getProjectName(){
    var curWwwPath=window.document.location.href;
    //获取主机地址之后的目录，如： myproj/view/my.jsp
    var pathName=window.document.location.pathname;
    var pos=curWwwPath.indexOf(pathName);
    //获取主机地址，如： http://localhost:8083
    var localhostPaht=curWwwPath.substring(0,pos);
    //获取带"/"的项目名，如：/myproj
    var projectName=pathName.substring(0,pathName.substr(1).indexOf('/')+1);
    //得到了 http://localhost:8083/myproj
    var curWwwPath=window.document.location.href;
    //获取主机地址之后的目录，如： myproj/view/my.jsp
    var pathName=window.document.location.pathname;
    var pos=curWwwPath.indexOf(pathName);
    //获取主机地址，如： http://localhost:8083
    var localhostPaht=curWwwPath.substring(0,pos);
    //获取带"/"的项目名，如：/myproj
    var projectName=pathName.substring(0,pathName.substr(1).indexOf('/')+1);
    return projectName;
}

计算两个日期相差多少时间，工具

转载地址：https://blog.csdn.net/qq_40591925/article/details/87856414

function dayCha(time, twoTime) {
  time = time.replace(new RegExp("-", "gm"), "/");
  if (twoTime) {
    twoTime = twoTime.replace(new RegExp("-", "gm"), "/");
  }
  else {
    twoTime = new Date();
  }
  // 计算比较日期
  const getMaxMinDate = (time, twoTime, type) => {
    let minTime = new Date(time).getTime() - new Date(twoTime).getTime() > 0 ? twoTime : time
    let maxTime = new Date(time).getTime() - new Date(twoTime).getTime() > 0 ? time : twoTime
    let maxDateDay = new Date(new Date(maxTime).getFullYear(), new Date(maxTime).getMonth() + 1, 0).getDate()
    let maxMinDate = new Date(minTime).getDate() > maxDateDay ? maxDateDay : new Date(minTime).getDate()
    let maxMinTong = null
    if (type == 'month') {
      maxMinTong = new Date(maxTime).getFullYear() + '/' + (new Date(minTime).getMonth() + 1) + '/' + maxMinDate + ' ' + new Date(minTime).toLocaleTimeString('chinese',{hour12:false})
    } else {
      maxMinTong = new Date(maxTime).getFullYear() + '/' + (new Date(maxTime).getMonth() + 1) + '/' + maxMinDate + ' ' + new Date(minTime).toLocaleTimeString('chinese',{hour12:false})
    }
    return {
      minTime,
      maxTime,
      maxMinTong
    }
  }
  // 相差年份
  const getYear = (time, twoTime) => {
    let oneYear = new Date(time).getFullYear()
    let twoYear = new Date(twoTime).getFullYear()
    // 计算出与最小日期的日时分相同的最大日期的值
    // 如2016-8-17和2019-6-30,计算出来的maxMinTong为2019-8-17
    const { minTime, maxTime, maxMinTong } = getMaxMinDate(time, twoTime, 'month')
    // 计算相差多少年
    let chaYear = Math.abs(oneYear - twoYear)
    // 如果计算出的maxMinTong(如2019-8-17)大于了最大日期,则表示最后一年没有满,需要减一
    if (new Date(maxMinTong).getTime() > new Date(maxTime).getTime()) {
      chaYear--
    }
    return chaYear
  }
  const getMonthTong = (time, twoTime) => {
    let oneMonth = new Date(time).getFullYear() * 12 + (new Date(time).getMonth() + 1)
    let twoMonth = new Date(twoTime).getFullYear() * 12 + (new Date(twoTime).getMonth() + 1)
    return Math.abs(oneMonth - twoMonth)
  }
  // 相差月份
  const getMonth = (time, twoTime, value) => {
    // 计算出与最小日期的日时分相同的最大日期的值
    // 如2016-8-17和2019-6-30,计算出来的maxMinTong为2019-6-17
    const { minTime, maxTime, maxMinTong } = getMaxMinDate(time, twoTime, 'day')
    // 计算最小日期到maxMinTong(如2019-6-17)的月份,这样刚好对应月日
    let chaMonth = getMonthTong(minTime, maxMinTong)
    // 如果计算出来的maxMinTong(如2019-6-17)大于最大日期,则表示最后一月没有满,需要减一
    if (new Date(maxMinTong).getTime() > new Date(maxTime).getTime()) {
      chaMonth--
    }
    if (value) {
      return chaMonth - value
    } else {
      return chaMonth
    }
  }
  // 相差天数
  const getDay = (time, twoTime, value) => {
    let chaTime = Math.abs(new Date(time).getTime() - new Date(twoTime).getTime());
    if (value) {
      return parseInt(chaTime / 86400000) - value
    } else {
      return parseInt(chaTime / 86400000)
    }
  }
  // 相差小时
  const getHour = (time, twoTime, value) => {
    let chaTime = Math.abs(new Date(time).getTime() - new Date(twoTime).getTime());
    if (value) {
      return parseInt(chaTime / 3600000) - value
    } else {
      return parseInt(chaTime / 3600000)
    }
  }
  // 相差分钟
  const getMinute = (time, twoTime, value) => {
    let chaTime = Math.abs(new Date(time).getTime() - new Date(twoTime).getTime());
    if (value) {
      return parseInt(chaTime / 60000) - value
    } else {
      return parseInt(chaTime / 60000)
    }
  }
  // 相差秒
  const getSecond = (time, twoTime, value) => {
    let chaTime = Math.abs(new Date(time).getTime() - new Date(twoTime).getTime());
    if (value) {
      return parseInt(chaTime / 1000) - value
    } else {
      return parseInt(chaTime / 1000)
    }
  }
  // 相差年月日时分秒
  const getDffeYMDHMS = (time, twoTime) => {
    // 计算出与最小日期的日时分相同的最大日期的值
    // 如2016-8-17和2019-6-30,计算出来的maxMinTong为2019-6-17
    const { minTime, maxTime, maxMinTong } = getMaxMinDate(time, twoTime, 'day')
    // 计算最小日期到(如:2019-6-17)的天数,这样算出来的天数刚好数足月的
    let dffeDay1 = getDay(minTime, maxMinTong)
    // 判断一下,如果计算出来的(如:2019-6-17)大于最后的日期(如2019-6-30)就需要减去(2019-6-30到2019-6-17的天数,否则不需要)
    if (new Date(maxMinTong).getTime() > new Date(maxTime).getTime()) {
      let prevMonth = new Date(maxMinTong).getMonth() - 1
      let lastTime=new Date(maxMinTong).setMonth(prevMonth)
      dffeDay1 = dffeDay1 - getDay((new Date(lastTime).getFullYear() + '/' + (new Date(lastTime).getMonth()+1) + '/' + new Date(lastTime).getDate()), maxMinTong)
    }
    let dffeYear = getYear(time, twoTime)
    let dffeMonth = getMonth(time, twoTime, dffeYear * 12)
    let dffeDay = getDay(time, twoTime, dffeDay1)
    let dffeHour = getHour(time, twoTime, getDay(time, twoTime) * 24)
    let dffeMinute = getMinute(time, twoTime, (getDay(time, twoTime) * 24 * 60 + dffeHour * 60))
    let dffeSecond = getSecond(time, twoTime, (getDay(time, twoTime) * 24 * 60 * 60 + dffeHour * 60 * 60 + dffeMinute * 60))
    console.log(`年:${dffeYear},月:${dffeMonth},日:${dffeDay},时:${dffeHour},分:${dffeMinute},秒:${dffeSecond}`)
    return { dffeYear, dffeMonth, dffeDay, dffeHour, dffeMinute, dffeSecond }
  }
  // 相差年月周日时分秒
  const getDffeYMWDHMS = (time, twoTime) => {
    // 计算出与最小日期的日时分相同的最大日期的值
    const { minTime, maxTime, maxMinTong } = getMaxMinDate(time, twoTime, 'day')
    let dffeDay1 = getDay(minTime, maxMinTong)
    // 如果大于了,就需要减掉多余天数
    if (new Date(maxMinTong).getTime() > new Date(maxTime).getTime()) {
      let prevMonth = new Date(maxMinTong).getMonth() - 1
      let lastTime=new Date(maxMinTong).setMonth(prevMonth)
      dffeDay1 = dffeDay1 - getDay((new Date(lastTime).getFullYear() + '/' + (new Date(lastTime).getMonth()+1) + '/' + new Date(lastTime).getDate()), maxMinTong)
    }
    let dffeYear = getYear(time, twoTime)
    let dffeMonth = getMonth(time, twoTime, dffeYear * 12)
    let dffeDayZong = getDay(time, twoTime, dffeDay1)
    let dffeWeek = parseInt(dffeDayZong / 7)
    let dffeDay = dffeDayZong - dffeWeek * 7
    let dffeHour = getHour(time, twoTime, getDay(time, twoTime) * 24)
    let dffeMinute = getMinute(time, twoTime, (getDay(time, twoTime) * 24 * 60 + dffeHour * 60))
    let dffeSecond = getSecond(time, twoTime, (getDay(time, twoTime) * 24 * 60 * 60 + dffeHour * 60 * 60 + dffeMinute * 60))
    console.log(`年:${dffeYear},月:${dffeMonth},周:${dffeWeek},日:${dffeDay},时:${dffeHour},分:${dffeMinute},秒:${dffeSecond}`)
    return { dffeYear, dffeMonth, dffeWeek, dffeDay, dffeHour, dffeMinute, dffeSecond }
  }
 
  let chaYear = getYear(time, twoTime)
  let chaMonth = getMonth(time, twoTime)
  let chaDay = getDay(time, twoTime)
  let chaHour = getHour(time, twoTime)
  let chaMinute = getMinute(time, twoTime)
  let chaSecond = getSecond(time, twoTime)
  return {
    chaYear, chaMonth, chaDay, chaHour, chaMinute, chaSecond,
    getDffeYMDHMS: getDffeYMDHMS(time, twoTime),
    getDffeYMWDHMS: getDffeYMWDHMS(time, twoTime)
  }
 
}

纯html+js编程，前端存储状态数据

相关笔记：

• https://blog.csdn.net/ITsmallchen/article/details/109398588
• https://juejin.cn/post/7203569814181986364

项目错误笔记

修改一个对象的值，另一个对象也改变

当两个对象引用了同一个对象时，一个对象的值发生变动，另一个也会发生改变

解决方法：将对象想办法copy一份再赋值，让两个对象不再使用同一个内存地址

例如：将对象转换为 json字符串 ，再转换回来

目标对象 = JSON.parse(JSON.stringify(源对象))

数字 Infinity

数字计算的结果为Infinity是因为计算错了

因为某个值或因为某一些值的原因，导致计算结果过大。需要仔细排查