如何扩展类似bootstrap-typeahead.js的库

Question

Let's suppose I would like to add some functionalities to the original bootstrap-typeahead.js.
I don't like the idea to fork another library and then edit it to add functionalities or use a forked library.

One use case could be: adding the option onselect to $.fn.typeahead.defaults in order to execute a callback when I select an item in autocomplete.

This is my test (1), please add comments and code to make it working.

---

(1)

_.extend($.fn.typeahead.defaults, {onselect: null});

element.typeahead({
    minLength: 3,
    source: function () {
        return ['val1', 'val2'];
    },
    onselect: function (val) {
      console.log(val); // it should be able to get the value selected  
    }
});

Answer 1

JavaScript is a very dynamic language which allows you to easily redefine or modify functions at run-time. See this answer of mine for an example.

However, it would appear that someone has already answered your question by linking to a forked typeahead to provide an onselect callback.