【自用】【JS】 月份转换 201909，202009，202010转成2019年09月、2020年09月、10月

    formatMon: function(value) {
      if (value != undefined && value != null && value != "") {
        var strs = new Array(); //定义一数组
        strs = value.split(","); //字符分割

        var years = new Map();

        for (var i = 0; i < strs.length; i++) {
          var str = strs[i];
          var year = str.substring(0, 4);
          var mon = str.substring(4);
          if (years.has(year)) {
            var m = years.get(year);
            m = m + mon + "月、";
            years.set(year, m);
          } else {
            years.set(year, mon + "月、");
          }
        }

        var s = "";
        years.forEach(function(value, key, map) {
          s = s + key + "年" + value;
        });
        s = s.substring(0, s.length - 1);
        return s;
      }

      return "";
    }

来源：CSDN

作者：qq_36757824

链接：https://blog.csdn.net/qq_36757824/article/details/104406341