Question

with reference of this question Sort json array

I have the following JSON String using ajax and store the object as an array:

var homes = [
    {
     "h_id":"3",
     "city":"Dallas",
     "state":"TX",
     "zip":"75201",
     "price":"162500",
     "start_time":"2011-01-26 08:00:00",
     "end_time":"2011-01-26 05:00:00"
    },
    {
     "h_id":"4",
     "city":"Bevery Hills",
     "state":"CA",
     "zip":"90210",
     "price":"319250",
     "start_time":"2011-01-26 12:00:00",
     "end_time":"2011-01-26 05:00:00"
    },
    {
     "h_id":"5",
     "city":"New York",
     "state":"NY",
     "zip":"00010",
     "price":"962500",
     "start_time":"2011-01-28 08:00:00",
     "end_time":"2011-01-26 05:00:00"
    }
    ];

How do I create a function to sort the “start_date” field in ASC and also sort in DESC ordering using only JavaScript?

i used below function suggested by Triptych

var sort_by = function(field, reverse, primer){

   reverse = (reverse) ? -1 : 1;

   return function(a,b){

       a = a[field];
       b = b[field];

       if (typeof(primer) != 'undefined'){
           a = primer(a);
           b = primer(b);
       }

       if (a<b) return reverse * -1;
       if (a>b) return reverse * 1;
       return 0;

   }
}

and apply in below manner

// Sort by start_time
homes.sort(sort_by('start_time', false, function(a){return a.getTime()}));

but not working..:((, give this error

a.getTime is not a function

please tell me where i m doing mistake..

Thanks in advance

Note: sorry for copying same
question…

Answer 1

As I said in the comment, a string does not have a getTime() method. Only Date objects have. Therefore you have to convert the date string into a Date object. Change your function to:

function(a){return (new Date(a)).getTime()}

Now, there are various implementations of Date and I think only the newer ones support parsing of this kind of date string (not sure though). Maybe you have to parse the string first and pass the single values to Date:

function(a){
    var parts = a.match(/(\d{4})-(\d{2})-(\d{2}) (\d{2}):(\d{2}):(\d{2})/);
    var date = new Date(parts[1], parts[2], parts[3], parts[4], parts[5], parts[6]);
    return date.getTime()}
}

Reference: Date