I have the following
var my_date = '2021-09-27';
my_date = new Date(my_date);
var new_date = new Date();
for(var i=0; i<10; i++)
{
new_date.setDate(my_date.getDate() + i);
var this_date = new_date.toISOString();
console.log(this_date);
}
I was expecting it to output
2021-09-27T19:21:26.361Z
2021-09-28T19:21:26.361Z
2021-09-29T19:21:26.361Z
2021-09-30T19:21:26.361Z
2021-10-01T19:21:26.361Z
2021-10-02T19:21:26.361Z
2021-10-03T19:21:26.361Z
2021-10-04T19:21:26.361Z
2021-10-05T19:21:26.361Z
2021-10-06T19:21:26.361Z
but for some reason it outputs
2021-10-27T19:21:26.361Z
2021-10-28T19:21:26.361Z
2021-10-29T19:21:26.361Z
2021-10-30T19:21:26.361Z
2021-10-31T19:21:26.361Z
2021-11-01T19:21:26.361Z
2021-12-03T19:21:26.361Z
2022-01-03T19:21:26.361Z
2022-02-04T19:21:26.361Z
2022-03-08T19:21:26.361Z
As you can see it starts in October not September, and then when it hits the 31st it starts to jump months.
Why is this script behaving like this?
All the examples I have found online seem to suggest this would work.
Thanks
Because setDate only changes days, so when you create new Date() it has current month in it. You have to copy original date to make this works properly.
Here's the fix:
var my_date = '2021-09-27';
my_date = new Date(my_date);
for(var i=0; i<10; i++)
{
// clone date
var new_date = new Date(my_date.getTime())
new_date.setDate(my_date.getDate() + i);
var this_date = new_date.toISOString();
console.log(this_date);
}