如何按日期对Javascript对象数组进行排序？

Question

I have a problem to sort my object arrays by Date values. I found many questions that other users asked before, I went through all possible solutions and I still did not get solution for my sorting problem. I created two different arrays to test sort function too but still could not get dates in correct order. Here is my data:

[Object { eventDate="12/12/2016",  display_order="5"},Object { eventDate="12/12/2016",  display_order="3"}]

[Object { eventDate="04/21/2016",  display_order="3"},Object { eventDate="04/21/2016",  display_order="1"}]

I used this logic to sort my data by date values:

entries.sort(function(a,b){
    var i = new Date(a.eventDate);
    var j = new Date(b.eventDate);
    return i-j;
});

My data still did not sort in correct order using this function. Then I also tried to sort my array that looks like this:

var dates = Object.keys(groupedByDate);

console.log(dates)

This is output for variable dates: ["12/12/2016", "04/21/2016"]

Then I tried to do this:

dates.sort(function(a, b) {
    a = new Date(a.dates);
    b = new Date(b.dates);
    return a>b ? -1 : a<b ? 1 : 0;
});

My output still did not sort my dates in correct order. I'm not sure am I doing something wrong or something else could be a problem in this case. If anyone can help please let me know. Thanks.

Answer 1

Sort dates using Date.getTime() function ( by number of milliseconds ):

dates.sort(function(a, b) {
    a = (new Date(a.dates)).getTime();
    b = (new Date(b.dates)).getTime();
    return a - b;
});

Answer 2

You could split the date and sort with the parts.

 var array = [{ eventDate: "12/12/2016", display_order: "5" }, { eventDate: "12/12/2016", display_order: "3" }, { eventDate: "04/21/2016", display_order: "3" }, { eventDate: "04/21/2016", display_order: "1" }]; array.sort(function (a, b) { var aa = a.eventDate.split('/'), bb = b.eventDate.split('/'); return aa[2] - bb[2] || aa[0] - bb[0] || aa[1] - bb[1]; }); document.write('<pre>' + JSON.stringify(array, 0, 4) + '</pre>'); 

Answer 3

Seems there is an issue in the json you pasted. { eventDate="12/12/2016", display_order="3"} .Instead of = it has to be : Assuming you have correct json format the below solutions can be useful

var array = [{ eventDate:"12/12/2016",  display_order:"5"}, 
                { eventDate:"12/12/2016",  display_order:"3"},
                { eventDate:"04/21/2016",  display_order:"3"},
                { eventDate:"04/21/2016",  display_order:"1"}];

// Generic solution
var sortedArray = array.sort(function(a,b) { 
    return new Date(a.eventDate).getTime() - new Date(b.eventDate).getTime() 
});


// Solution using ternary operator
var l =array.sort(function(a,b){
  return a.eventDate>b.eventDate ? -1 : a.eventDate<b.eventDate ? 1 : 0;
});

Demo

Answer 4

The answers here are on the right track but you should never use the Date constructor, or Date.parse, to parse strings. Use a library and pass the format, or write a simple function, eg

 function parseMDY(s) { var b = s.split('/'); return new Date(b[2],b[0]-1,b[1]); } document.write(parseMDY('4/30/2016')); 

So now you have:

entries.sort(function(a,b) {
  return parseMDY(a) - parseMDY(b);
});

Answer 5

So I tried all answers above, some of them gave me close but not fully solution for my case. So I just tried to combine and this is correct solution for my problem:

dates.sort(function(a, b) {
    return new Date(a).getTime() - new Date(b).getTime();
});

If I tried to return just A and B, that worked for one record, but then when I switch user in my onChange drop down I was getting reverse dates again. So solution above with new Date() and getTime() works fine. Thank you all for your help!