我正在处理Javascript日期，我一直在为一个日期增加7天

Question

var date = new Date();
var first_date = new Date(date); //Make a copy of the date we want the first and last days from
first_date.setUTCDate(1); //Set the day as the first of the month

var firstDay = first_date.toJSON().substring(0, 10);  
console.log(firstDay)

1. 我正在处理Javascript日期，我一直在为这个日期增加7天
2. 提前感谢

Answer 1

var date = new Date();
var first_date = new Date(date); //Make a copy of the date we want the first and last days from
first_date.setUTCDate(1); //Set the day as the first of the month

var firstDay = first_date.toJSON().substring(0, 10);
var resultDate = new Date();
resultDate.setDate(first_date.getDate() + 7);
var resultDay = resultDate.toJSON().substring(0, 10); 
console.log("First day: " + firstDay)
console.log("7 days from specific day: " + resultDay)