I tried this:
$("#typeahead_object").val("test");
It only changes the textbox value but doesn't trigger the 'updater' function of the typeahead.
Question : How can I set the value of a typeahead object manually and trigger its updater function?
To change typeahead input value, use the following construction:
$(input).typeahead('val',value);
So, in your case it should looks like:
$("#typeahead_object").typeahead('val',"test");
typeahead API documentation is available on https://github.com/twitter/typeahead.js/blob/master/doc/jquery_typeahead.md#datasets