js 计算前一天

function getPreviousDay(date) {
    // 创建一个新的 Date 对象，避免修改原始日期
    let previousDay = new Date(date);
    // 使用 setDate 方法减去 1 天
    previousDay.setDate(previousDay.getDate() - 1);
    return previousDay;
}

// 使用示例
let today = new Date();
let yesterday = getPreviousDay(today);
console.log(yesterday.toDateString()); // 输出前一天的日期，例如 "Mon Oct 23 2023"

function getPreviousDayWithoutTime(date) {
    let previousDay = new Date(date);
    previousDay.setDate(previousDay.getDate() - 1);
    previousDay.setHours(0, 0, 0, 0); // 设置时间为 00:00:00
    return previousDay;
}