合并对象 时间格式化 判断是否今天 差几天，过去几天

// https://segmentfault.com/q/1010000005018933#answer-1020000005019144
if (!Object.assign) {
  Object.defineProperty(Object, "assign", {
    enumerable: false,
    configurable: true,
    writable: true,
    value: function(target, firstSource) {
      "use strict";
      if (target === undefined || target === null)
        throw new TypeError("Cannot convert first argument to object");
      var to = Object(target);
      for (var i = 1; i < arguments.length; i++) {
        var nextSource = arguments[i];
        if (nextSource === undefined || nextSource === null) continue;
        var keysArray = Object.keys(Object(nextSource));
        for (var nextIndex = 0, len = keysArray.length; nextIndex < len; nextIndex++) {
          var nextKey = keysArray[nextIndex];
          var desc = Object.getOwnPropertyDescriptor(nextSource, nextKey);
          if (desc !== undefined && desc.enumerable) to[nextKey] = nextSource[nextKey];
        }
      }
      return to;
    }
  });
}

Number.prototype.formatTime = function () {
  // 计算
  var i = 0,
      s = parseInt(this)
  if (s > 60) {
      i = parseInt(s / 60)
      s = parseInt(s % 60)
  }
  // 补零
  var zero = function (v) {
      return v >> 0 < 10 ? '0' + v : v
  }
  return [zero(i), zero(s)].join(':')
}

[https://www.cnblogs.com/hwaggLee/p/4651892.html](https://www.cnblogs.com/hwaggLee/p/4651892.html)

Date.prototype.format = function(format){ 
  var o = { 
  "M+" : this.getMonth()+1, //month 
  "d+" : this.getDate(), //day 
  "h+" : this.getHours(), //hour 
  "m+" : this.getMinutes(), //minute 
  "s+" : this.getSeconds(), //second 
  "q+" : Math.floor((this.getMonth()+3)/3), //quarter 
  "S" : this.getMilliseconds() //millisecond 
  } 

  if(/(y+)/.test(format)) { 
  format = format.replace(RegExp.$1, (this.getFullYear()+"").substr(4 - RegExp.$1.length)); 
  } 
  var week = {         
      "0" : "一",         
      "1" : "二",         
      "2" : "三",         
      "3" : "四",         
      "4" : "五",         
      "5" : "六",         
      "6" : "日"        
      };  
  if(/(E+)/.test(format)){         
      format=format.replace(RegExp.$1, ((RegExp.$1.length>1) ? (RegExp.$1.length>2 ? "星期" : "周") : "")+week[this.getDay()+""]);         
  }    
  
  for(var k in o) { 
  if(new RegExp("("+ k +")").test(format)) { 
  format = format.replace(RegExp.$1, RegExp.$1.length==1 ? o[k] : ("00"+ o[k]).substr((""+ o[k]).length)); 
  } 
  } 
  return format; 
  }
// 使用new Date(time).format("MM月dd日 EE")
// 使用new Date(time).format("yyyy年MM月dd日 EEE")

# [js判断时间是否为今天日期（判断日期与当前日期相差多少天）](https://www.cnblogs.com/qiuxiaojian/p/9403215.html)

下面是我的代码：

// 判断时间为今天
judgeTime(data){
var date = data.toString();
var year = date.substring(0, 4);
var month = date.substring(4, 6);
var day = date.substring(6, 8);
var d1 = new Date(year + '/' + month + '/' + day);
var dd = new Date();
var y = dd.getFullYear();
var m = dd.getMonth() + 1;
var d = dd.getDate();
var d2 = new Date(y + '/' + m + '/' + d);
var iday = parseInt(d2 - d1) / 1000 / 60 / 60 / 24;
return iday;
},

var start_time="2018-07-31T14:00" //这是一般的时间格式，下面是使用replace方法进行转换为数字格
//式

if(judgeTime(start_time.replace(/-|T|:/g, ''))==0){
console.log('日期为今天')
}

如果数字为负数，-1为明天   负多少就是差多少    正数相反的道理