计算30天之前的日期

const ONE_MONTH = 24 * 60 * 60 * 1000 * 30;

...

getTime() {
	let time = new Date(new Date().setHours(0, 0, 0, 0));
    time = new Date(time.getTime() - ONE_MONTH);
    const requestTime = Number(`${time.getFullYear()}${time.getMonth() + 1}${time.getDate()}`);
    return requestTime;
}