8

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")

Brian Tompsett - 汤莱恩
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Leem
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4 Answers4

24

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 })
turdus-merula
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    Congratulations for having the only sane answer here. – Tom Jul 31 '17 at 16:20
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    You don't even need `new Date` at all if they are [valid date strings](https://stackoverflow.com/questions/51715259/what-are-valid-date-time-strings-in-javascript) in the same time zone. – str Dec 10 '18 at 12:28
11

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;
    }
});
Matt
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    I would start by defining a new field in each value with the date already parsed for efficiency. – Serabe Sep 22 '11 at 10:11
  • How about if it is not a list of objects, but a object which contain objects, and I would like to sort the objects inside a object? – Leem Sep 22 '11 at 10:13
  • @Leem: There is nothing in any standards which describes what order object members should be enumerated in (citation needed). You should convert the object to an array. – Matt Sep 22 '11 at 10:16
  • If `date` field always contains value as "2002-08-29 21:15:31+0500" and always have "+0500", then posible to compare they for sorting without parsing into `Date` object. – Andrew D. Sep 22 '11 at 10:20
2
yourArray.sort(function(a, b) { 
 a = new Date(a.date);
 b = new Date(b.date);
 return a >b ? -1 : a < b ? 1 : 0;
})
RredCat
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sd.n
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0

You can try: 

<script src="https://cyberknight.000webhostapp.com/arrange.js">
var a =[-1,0,5,4,3,2,6,1,1];
var b = totzarrange(a)
console.log(b);
</script>
as sdfas
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