简单的时间处理

function dateOperation(date = new Date()) {
    this.myDate = new Date(date);
    // 格式化时间
    this.getFormat = (format = 'YYYY-MM-DD HH:mm:ss', date = this.myDate) => {
        date = new Date(date);
        const config = {
            YYYY: date.getFullYear(),
            MM: this.repair(date.getMonth() + 1),
            DD: this.repair(date.getDate()),
            HH: this.repair(date.getHours()),
            mm: this.repair(date.getMinutes()),
            ss: this.repair(date.getSeconds()),
        }
        for (const configKey in config) {
            format = format.replace(configKey, config[configKey]);
        }
        return format;
    }
    // 补零
    this.repair = (month) => {
        return month < 10 ? '0' + month : month;
    }
    // 获取向前向后多少天的时间 以天数为单位
    this.getBeforeDate = (n, date = this.myDate) => {
        date = new Date(date);
        let calculation = 1000 * 60 * 60 * 24 * n;
        let getTimeStr = date.getTime();
        this.myDate = new Date(getTimeStr + calculation)
        return this;
    }
}

let date1 = new dateOperation();
console.log(date1.getFormat());
console.log(date1.getBeforeDate(5).getFormat())
console.log(date1.getFormat());