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EduBw
Asked: 2020-11-08 02:30:22 +0800 CST 2020-11-08 02:30:22 +0800 CST

Know which date is greater in Javascript

  • 772

I have 2 dates, one for start and one for end, I try to prevent the start date from being greater than the end date, apart from the fact that I can't do it, I get strange years, days that are not... etc.

                    console.log("start ", m , d ,  y);
                    console.log("fin ", m2 , d2, y2);

                    console.log("-------");

                    console.log("start", new Date(m, d, y));
                    console.log("fin", new Date(m2, d2, y2));

                    if (new Date(m, d, y) > new Date(m2, d2, y2)) {
                        format = false;
                        this.errorServer = true;
                        this.message = "La fecha de inicio no puede ser mayor que la fecha de fin.";
                    }

And the result:

enter image description here

As a result of this change, I don't get the error that the start date is greater...

javascript

2 Answers

  1. Best Answer

    You are using the constructor wrong, the correct thing is:

    new Date(year, month, day);

    But not only that, but the month starts at 0, then subtract 1:

    console.log("start", new Date(2018, 10, 6)); //ayer, a día de la creación de esta respuesta.
console.log("fin", new Date()); //ahora

console.log(new Date(2018, 10, 6) > new Date());
console.log(new Date(2018, 10, 6) < new Date());

    Not only is the format a bit strange, but it's also always UTC time, so the first line in the console shows me "2018-11-05T23:00:00.000Z"why I'm in UTC+1, then the date 2018-11-06 (00:00: 00) has been delayed by one hour.

    • 4

  2. The problem is with the constructor for the date object, which must be new Date(year, monthIndex, day) where monthIndex must be indexed from 0 to 11.

    The standard operators >, <, <=or >=can normally be used to compare the Date type , however if you wish to use the operators ==, !=, ===, and !==you must convert the date to milliseconds using the getTime() method.

    var f1 = new Date();
var f2 = new Date(f1);
var iguales = f1.getTime() === f2.getTime();
var noIguales = f1.getTime() !== f2.getTime();

    Official Documentation

    • 1