code: function toJalaliFormat(format) {
      for (var i = 0; i < format.length; i++) {
          if(!i || (format[i-1] !== "j" && format[i-1] !== format[i])) {
              if (format[i] === "Y" || format[i] === "M" || format[i] === "D" || format[i] === "g") {
                  format = format.slice(0, i) + "j" + format.slice(i);
              }
          }
      }
      return format;
  }
docs: Changes any moment Gregorian format to Jalali system format
  @param {string} format
  @example toJalaliFormat("YYYY/MMM/DD") => "jYYYY/jMMM/jDD"