multitype.js

turnHashtagsToTags: function () {
            var $this = $(this);
            var inputting;
            var inputPosition;
            var charsEntered;
            var actualValue;

            function commit(){
                var $tagsInput = $('.bootstrap-tagsinput input');
                if (inputting) {
                    inputting = false;
                    if (charsEntered){
                        // Press ENTER on the tags field
                        $tagsInput.trigger(jQuery.Event('keypress', { which: 13 }));
                    }
                }
            }

            function start(){
                inputting = true;
                actualValue = '';
                charsEntered = 0;
                inputPosition = 0;
            }

            function charIsValid(char){
                return char.match(/[a-z0-9_-]/i) && !(char.match(/\d/) && !charsEntered)
            }

            function setValue(val){
                var $tagsInput = $('.bootstrap-tagsinput input');
                actualValue = val;
                var validVal = _.select(val, function(c){ return charIsValid(c) }).join('');
                $tagsInput.val(validVal.toLowerCase());
            }

            function add(code){
                var char = String.fromCharCode(code);
                if (inputting) {
                    inputPosition++;
                    charsEntered++;
                    var initialVal = actualValue;
                    var beforeInputPosition = initialVal.slice(0, inputPosition - 1);
                    var afterInputPosition = initialVal.slice(inputPosition - 1, initialVal.length);
                    var newVal = beforeInputPosition + char + afterInputPosition;
                    setValue(newVal);
                }
            }

            function subtract(){
                if (inputting) {
                    inputPosition--;
                    charsEntered--;
                    var initialVal = actualValue;
                    var newVal = initialVal.substring(0, initialVal.length - 1);
                    setValue(newVal);
                    if (charsEntered < 0){ commit() }
                }
            }

            $this.on('click', function(){
                commit();
            });

            $this.on('keyup', function(){
                var code = event.which;
                switch (code) {
                    case 8: // BACKSPACE
                        subtract();
                        break;
                    case 38: // UP ARROW
                        commit();
                    case 39: // RIGHT ARROW
                        inputPosition++;
                        if (inputPosition > charsEntered){ commit() }
                        break;
                    case 40: // DOWN ARROW
                        commit();
                        break;
                    case 32: // 'SPACE'
                        commit();
                        break;
                    case 13: // 'ENTER'
                        commit();
                        break;
                    case 37: // LEFT ARROW
                        inputPosition--;
                        if (inputPosition < 0){ commit() }
                        break;
                }
            });

            $this.on('keypress', function(){
                var code = event.which;
                switch (code) {
                    case 35: // #
                        commit();
                        start();
                        break;
                    default: // Anything else
                        add(code);
                }
            })
        }