CODEWITHSUNDEEP
javascriptdate
Mike Sav
Mike Sav

Reputation: 15311

Outputting dates in a JavaScript loop from today until specific number of days

Before I start let me just say how much I hate the JavaScript Date() object! I really hate it and I would usually use a library like date.js however I have to use my own JavaScript for this problem....

Okay, I wish to create an array of dates from today until a specific date or for a specific number of days... in this example I will set it for a number of specific days (like 365). I will use this array to populate a select in my application later.

I wish to capture today's date, then add an integer to it to get the next date, then the next, etc, etc... and format these dates as dd/mm/yyyy (I haven't included this part).

So here is my code and I have noticed that my loop starts to jump/miss days after the second index/loop

 var today = new Date(),
     dd = today.getDate(),
     mm = today.getMonth() + 1,
     yyyy = today.getFullYear(),
     today,
     startDate,
     d,
     i,
     dateArray = [];

    if( dd < 10 ){
        dd='0' + dd
    } 

    if( mm < 10 ){
        mm='0' + mm
    }

    startDate = yyyy +'-'+ mm +'-' + dd;
    d = new Date(startDate)

    for(i = 0; i < 365; i++){
        d.setDate(d.getDate() + i);
            // I will format 'd' to dd/mm/yyyy later
            dateArray.push(d)
        console.log(d);
    }

My console is logging the following (I have shown the first 4 outputs to demonstrate my problem), notice how we miss Friday, then Sunday and Monday:

> Wed Apr 16 2014 02:00:00 GMT+0200 (CEST) 
> Thu Apr 17 2014 02:00:00 GMT+0200 (CEST) 
> Sat Apr 19 2014 02:00:00 GMT+0200 (CEST) 
> Tue Apr 22 2014 02:00:00 GMT+0200 (CEST)

I am obviously going about this the wrong way can someone please advise me on how to use the Date() object correctly and where I am going wrong with my loop.

Thanks in advance

Upvotes: 0

Views: 958

Answers (2)

dkasipovic
dkasipovic

Reputation: 6120

You are using the same object over and over. Take this for example:

  1. You start with Apr 16th
  2. You add 1 to Apr 16th, and it becomes Apr 17th
  3. Now you add 2 to the date, which at the moment is Apr 17th, so it becomes Apr 19th
  4. Now you add 3 to the date, which at the moment is Apr 19th, so it becomes Apr 22nd
  5. ...

You should see what I am talking about. Finally, you should do something like this:

d = new Date(startDate)

for(i = 0; i < 365; i++){
  c = new Date().setDate(d.getDate() + i);
  dateArray.push(c)
  console.log(c);
}

Or as the Tom Fenech said, you can just add +1 instead of +i to your current date object (d).

Upvotes: 1

Tom Fenech
Tom Fenech

Reputation: 74665

Due to your loop, you're adding 1, 2, then 3 to d. If you want them to be consecutive you change + i to + 1, like:

for(i = 0; i < 365; i++){
    d.setDate(d.getDate() + 1);
    // I will format 'd' to dd/mm/yyyy later
    dateArray.push(d)
    console.log(d);
}

Upvotes: 2

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