Add date into array as YYYY-M-DD in reactjs - reactjs

Question

Now I have a textarea which I enter the date in format 2019-09-15, But I want the date to be printed as 2019-9-15, here is my approach
getDifferenceInDays(startDate, endDate) {
let dateArray = [];
let currentDate = new Date(startDate);
let day = currentDate.getDate() + 1;
let month = currentDate.getMonth() + 1;
let year = currentDate.getFullYear();
currentDate = [year, month, day].join("-");
let endOfDate = new Date(endDate);
let endDay = endOfDate.getDate() + 1;
let endMonth = endOfDate.getMonth() + 1;
let endYear = endOfDate.getFullYear();
endOfDate = [endYear, endMonth, endDay].join("-");
let todayDate = new Date(currentDate);
while (todayDate <= new Date(endOfDate)) {
dateArray.push(currentDate);
todayDate = todayDate.addDays(1);
# currentDate = currentDate.setDate(currentDate.getDate() + 1);
}
return dateArray;
Now I am getting the currentDate as 2019-9-15, but if the startDate is 2019-09-15 and endDate is 2019-09-17 then the currentDate has to be updated like
2019-9-15
2019-9-16
2019-9-17
The line # when I debugged, it says currentDate.setDate as undefined, any solutions to this ? if it helps the entire line throws error
In short I want the date to be displayed as 2019-9-15 and it should increase as per the endate

Answer 1

There are some mistakes in your code.Fyi, you can compare dates using getTime() method of Date object. Here is a full demo how you can generate date and show date from startDate to endDate in a format you mentioned (YYYY-M-DD).The input here is static, just for demo purpose. Obviously, you could make it dynamic on your own.
function getDifferenceInDays(startDate, endDate) {
let dateArray = [];
let currentDate = new Date(startDate);
let day = currentDate.getDate();
let month = currentDate.getMonth()+1;
let year = currentDate.getFullYear();
currentDate = [year, month, day].join("-");
let endOfDate = new Date(endDate);
let endDay = endOfDate.getDate();
let endMonth = endOfDate.getMonth()+1;
let endYear = endOfDate.getFullYear();
endOfDate = [endYear, endMonth, endDay].join("-");
let todayDate = new Date(currentDate);
while (new Date(todayDate).getTime() <= new Date(endOfDate).getTime()) {
let formatTodayDate = new Date(todayDate).getFullYear() +'-'+ (new Date(todayDate).getMonth() + 1) +'-'+ new Date(todayDate).getDate()
dateArray.push(formatTodayDate);
todayDate = new Date(todayDate).setDate(new Date(todayDate).getDate()+1);
}
let demo = document.getElementById("demo")
demo.innerHTML = dateArray
//return dateArray;
}
<button type="button" onclick="getDifferenceInDays('2019-05-15', '2019-05-20')">Show Date</button>
<div id="demo"></div>

Answer 2

currentDate = [year, month, day].join("-");
Strings don't have a setDate method.
Logging the data you're operating on (or inspecting it at a breakpoint) would have shown you the problem immediately, and it would have been faster than asking on SO.