How to sort objects by date ascending order?

Question

If I have a list of object:

var objectList= LIST_OF_OBJECT;

each object in the list contains three attributes: "name", "date","gender"

How to sort the objects in the list by "date" attribute ascending order?

(the "date" attribute contain string value like "2002-08-29 21:15:31+0500")

Answer 1

If your objects have the date information within a String field:

yourArray.sort(function(a, b) { return new Date(a.date) - new Date(b.date) })

or, if they have it within a Date field:

yourArray.sort(function(a, b) { return a.date - b.date })

Answer 2

The Array.sort method accepts a sort function, which accepts two elements as arguments, and should return:

• < 0 if the first is less than the second
• 0 if the first is equal to the second
• > 0 if the first is greater than the second.

.

objectList.sort(function (a, b) {
    var key1 = a.date;
    var key2 = b.date;

    if (key1 < key2) {
        return -1;
    } else if (key1 == key2) {
        return 0;
    } else {
        return 1;
    }
});

You're lucky that, in the date format you've provided, a date that is before another date is also < than the date when using string comparisons. If this wasn't the case, you'd have to convert the string to a date first:

objectList.sort(function (a, b) {
    var key1 = new Date(a.date);
    var key2 = new Date(b.date);

    if (key1 < key2) {
        return -1;
    } else if (key1 == key2) {
        return 0;
    } else {
        return 1;
    }
});