1. .isLeap() > 判断当月是否闰月，是返回true，否返回false ### 示例代码 ``` let lunarMonth = LunarMonth.fromYm(2020, 4); console.log(lunarMonth.isLeap()); lunarMonth = LunarMonth.fromYm(2020, -4); console.log(lunarMonth.isLeap()); ```