减去迄今为止的循环

Question

Here's the code :

    var date = new Date(annee, mois, jour);
    var i = 0;
    while (i < 365) {
        date.setTime(date.getTime()-(1000*60*60*24*i));
        console.log(date.getFullYear()+'/'+parseInt(date.getMonth()+1)+'/'+date.getDate());
        i++;
    }

I'm trying to substract 1 day per loop, but i get this :

2016/1/13
2016/1/11
2016/1/8
2016/1/4
2015/12/30
2015/12/24
2015/12/17
2015/12/9
2015/11/30
2015/11/20
[...]
1834/2/27

after a quick look on stack's solution, I found this : Finding date by subtracting X number of days from a particular date in Javascript But the result is always a bunch of false days ... I tried by getDate()-days , setTime(getTime()-(different ms calculs)) - as in code -, trying with utc gmt and iso ...

well ... hope someone can help me :/ thanks !

Answer 1

Remove multiplication by i. It subtracts i days.

var date = new Date(annee, mois, jour);
    var i = 0;
    while (i < 365) {
        date.setTime(date.getTime()-(1000*60*60*24)); //removed *i
        console.log(date.getFullYear()+'/'+parseInt(date.getMonth()+1)+'/'+date.getDate());
        i++;
    }

Answer 2

Dates are really hard. Even though it seems like an easy calculation, what happens if the date is the first of the month - would you expect the date to rollback to the last month? What if it is the first day of the year? Or the 1st March and it is a leap year?

I'd recommend deferring tasks like this to a library such as http://momentjs.com/ or http://sugarjs.com/dates .