js获取当月第一天和最后一天

function getFirstDayOfMonth() {
    const today = new Date();
    const firstDay = new Date(today.getFullYear(), today.getMonth(), 1);
    return firstDay;
}

console.log(getFirstDayOfMonth()); // 输出当前月的第一天，例如：Mon Apr 01 2024 00:00:00 GMT+0800 (中国标准时间)

function getLastDayOfMonth() {
    const today = new Date();
    const lastDay = new Date(today.getFullYear(), today.getMonth() + 1, 0);
    return lastDay;
}

console.log(getLastDayOfMonth()); // 输出当前月的最后一天，例如：Sun Apr 30 2024 00:00:00 GMT+0800 (中国标准时间)

function formatDate(date) {
    const year = date.getFullYear();
    const month = String(date.getMonth() + 1).padStart(2, '0'); // 月份从0开始，需要加1
    const day = String(date.getDate()).padStart(2, '0');
    return `${year}-${month}-${day}`;
}

const firstDay = getFirstDayOfMonth();
const lastDay = getLastDayOfMonth();

console.log(formatDate(firstDay)); // 输出格式化的当月第一天，例如：2024-04-01
console.log(formatDate(lastDay)); // 输出格式化的当月最后一天，例如：2024-04-30