Proper usage of jQuery select2's initSelection callback with remote data

Question

I use jQuery select2 plugin in order to retrieve postcodes using the provided ajax callback function as follows:

$(document).ready(function() {
    $("#postcodes").select2({
        placeholder : "Search for a postcode",
        multiple : true,
        minimumInputLength : 3,
        ajax : {
            url : "/bignibou/utils/findGeolocationPostcodeByPostcodeStartingWith.json",
            dataType : 'json',
            data : function(term) {
                return {
                    postcode : term
                };
            },
            results : function(data) {
                console.log(data);
                return {
                    results : $.map(data, function(item) {
                        return {
                            id : item.id,
                            text : item.postcode
                        };
                    })
                };
            }
        }
    });
});

Once two postcodes are selected I get the resulting hidden input in the DOM:

<input type="hidden" class="bigdrop select2-offscreen" id="postcodes" style="width:600px" name="familyAdvertisement.postcodes" value="4797,4798" tabindex="-1">

The issue I have is that once the form is redisplayed (for instance in the event of some other controls being in error), the selections (ie the two postcodes and especially the text ) don't show in the form although the hidden input does have the two values (ie 4797 and 4798, which are the id s for the postcode).

I am not sure if I have to do another ajax round trip when the form is redisplayed or if there is a better way to go.

Can anyone please advise?

Answer 1

The initSelection method has to pass the values which has to be present in the select2

Ex:

$("#postcodes").select2({
    placeholder : "Search for a postcode",
    multiple : true,
    minimumInputLength : 1,
    data:[],
    initSelection : function (element, callback) {
        var data = [{id:1,text:'bug'},{id:2,text:'duplicate'}];
        callback(data);
    }
}).select2('val', ['1', '2']);

Demo: Fiddle