Twitter Bootstrap Typeahead force selection

I'm using the Bootstrap Typeahead plugin in my app, and here is my code (it's an example). I'm looking for a way to validate the selection of the user (basically if the input did not match any results -> empty the box on blur). The result must match. I searched everywhere and couldn't find a thing. Your help would be highly appreciated.

$('#search').typeahead({
    source: function (query, process) {
        var states = [];
        var map = {};

        var data = [
            { "stateCode": "CA", "stateName": "California" },
            { "stateCode": "AZ", "stateName": "Arizona" },
            { "stateCode": "NY", "stateName": "New York" },
            { "stateCode": "NV", "stateName": "Nevada" },
            { "stateCode": "OH", "stateName": "Ohio" }
        ];

        $.each(data, function (i, state) {
            map[state.stateName] = state;
            states.push(state.stateName);
        });

        process(states);
    }
});

If you extract out the data, states and map, you can then use them in the .blur function for lookup:

 var data = [
            { "stateCode": "CA", "stateName": "California" },
            { "stateCode": "AZ", "stateName": "Arizona" },
            { "stateCode": "NY", "stateName": "New York" },
            { "stateCode": "NV", "stateName": "Nevada" },
            { "stateCode": "OH", "stateName": "Ohio" }
        ];
 var states = [];
 var map = {};

 $.each(data, function (i, state) {
    map[state.stateName] = state;
    states.push(state.stateName);
 });

 $('#search').typeahead({
    source: function (query, process) {
        process(states);
    }
}).blur(function(){
    if(states[$(this).val()] == null) {
      $('#search').val('');
    }
});