excited.html

<div class="example-exclaimation">
  <input class="typeahead" type="text" placeholder="try it out">
</div>

excited.js

var anExcitedSource = function(query, cb) {
  var results = $.map(['!', '!!', '!!!'], function(appendage) {
    var datum = { theValue: query + appendage };

    return datum;
  });

  cb(results);
};

$('.example-exclaimation .typeahead').typeahead(null, {
  displayKey: 'theValue',
  source: anExcitedSource
});