<form ng-submit="addAssignment(assignName)">
  <div class="input-append">
    <input type="text" placeholder="Type a name" ng-model="assignName" ng-change="dostuff()" data-provide="typeahead" data-source="{{ teamNames }}">
    <button class="btn" type="submit">Add</button>
 </div>
</form>

$scope.addAssignment = function(name) {
    alert(name);
    return;
 }

angular.module('storageApp', []).directive('typeahead', function () {
return {
    restrict:'E',
    replace:true,
    scope:{
        model:'=',
        source:'&'
    },
    template:'<input type="text" ng-model="model"/>',
    link:function (scope, element, attrs) {
        console.log(scope.source);
        $(element).typeahead({
            source:scope.source,
            updater:function (item) {
                scope.$apply(read(item));
                return item;
            }
        });

        function read(value) {
            scope.model = value;
        }
    } // end link function
}; // end return
}); // end angular function

<typeahead id="addSupplier" model="addSupplier" placeholder="Skriv inn leverandør" class="typeahead" source="getSuppliers()" ></typeahead>