Select2 Loading remote data but params.page undefined

Question

Below is my code copied from https://select2.github.io/examples.html to load remote data via Select2 in my Asp.net MVC 4 project, which displayed in a Bootstap Modal dialog, however, it always shows "params.page" is undefined, it do worked if I put a "page:1" there. What's the problem?

$("#ReportToEmployeeName").select2({
        placeholder: "Select Report To",
        ajax: {
            url: 'myurl ',
            dataType: 'json',
            delay: 250,
            data: function (params) {
                console.log(params);
                return {
                    term: params.term, // search term
                    page: params.page //Undefined error here
                    //page: 1 // do worked, but then pagination will not work
                };
            },
            processResults: function(data, params) {
                params.page = params.page || 1;

                return {
                    results: data.Results,
                    pagination: {
                        more: (params.page * pageSize) < data.Total
                    }
                };
            },
            cache: true
        },
        //escapeMarkup: function (markup) { return markup; }, // let our custom formatter work
        minimumInputLength: 1,
        allowClear: true,
        //templateResult: formatRepo, // omitted for brevity, see the source of this page
        //templateSelection: formatRepoSelection // omitted for brevity, see the source of this page
    });