"Add new..." for Typeahead.js

typeahead_new.js

$(function() {

var source = new Bloodhound({
  /* create source as usual... */
});

source.initialize();

// Check if the query matches exactly
function noDirectMatch(matches, query) {
  if (matches.length > 0 ) {
    return matches[0][Object.keys(matches[0])[0]].toLowerCase() != query.toLowerCase();
  } else {
    return true
  }
};

// Create an intermediate typeahead source that adds a special "noMatch"
// suggestion unless the query matches exactly
var ttAdapter = function(query, cb) {
  source.get(query, function(matches) {
    if (noDirectMatch(matches, query)) {
      matches.push({
        noMatch: true,
        query: query
      });
    }
    cb(matches);
  });
};

var $input = $('#search');
$input.typeahead({}, {
  displayKey: 'name',
  source: ttAdapter,
  templates: {
    // Render the "noMatch" suggestion in a special way
    suggestion: function(suggestion) {
      if (suggestion.noMatch) {
        return "Add " + suggestion.query;
      } else {
        return suggestion.name;
      }
    }
  }
});

});