I am trying to implement [Bootstrap Tokenfield with Jquery Ui autocomplete](http://sliptree.github.io/bootstrap-tokenfield/#examples)
 and so far i was able to do that except the fact that i am not able to prevent duplicates in the input field, so, unfortunately my user can choose the same value twice. 

In my search i have found that Bootstrap Tokenfield has a way of [preventing duplicate](https://github.com/sliptree/bootstrap-tokenfield?files=1). However I do not know how to apply to my code because it looks to me that it goes with Twitter typeahead and not Jquery Ui.

How can i prevent duplicate with Bootstrap TokenField Using Jquery Ui autocomplete ?

This is my Bootstrap TokenField code based on jquery ui autocomplete

```
$('.tokenfield').tokenfield({
  autocomplete: {
    source: [
    {
        "id": "1",
        "value": "Ferdine Faithfull" 
    },
    {
        "id": "2",
        "value": "John Carta" 
    },
    {
        "id": "3",
        "value": "Mezane Smith" 
    }
    ],

    delay: 100
  },
  showAutocompleteOnFocus: true
});

```

And below is what i have found on Github to prevent duplicate though i think it is for Typeahead

```
$('#my-tokenfield').on('tokenfield:createtoken', function (event) {
    var existingTokens = $(this).tokenfield('getTokens');
    $.each(existingTokens, function(index, token) {
        if (token.value === event.attrs.value)
            event.preventDefault();
    });
});

```