LeaVerou/awesomplete

/**
 * Simple, lightweight, usable local autocomplete library for modern browsers
 * Because there weren’t enough autocomplete scripts in the world? Because I’m completely insane and have NIH syndrome? Probably both. :P
 * @author Lea Verou http://leaverou.github.io/awesomplete
 * MIT license
 */

(function () {

var _ = function (input, o) {
    var me = this;

    // Keep track of number of instances for unique IDs
    _.count = (_.count || 0) + 1;
    this.count = _.count;

    // Setup

    this.isOpened = false;

    this.input = $(input);
    this.input.setAttribute("autocomplete", "off");
    this.input.setAttribute("aria-autocomplete", "list");
    this.input.setAttribute("aria-expanded", "false");
    this.input.setAttribute("aria-owns", "awesomplete_list_" + this.count);
    this.input.setAttribute("role", "combobox");

    // store constructor options in case we need to distinguish
    // between default and customized behavior later on
    this.options = o = o || {};

    configure(this, {
        minChars: 2,
        maxItems: 10,
        autoFirst: false,
        data: _.DATA,
        filter: _.FILTER_CONTAINS,
        sort: o.sort === false ? false : _.SORT_BYLENGTH,
        container: _.CONTAINER,
        item: _.ITEM,
        replace: _.REPLACE,
        tabSelect: false,
        listLabel: "Results List",
        statusNoResults: "No results found",
        statusXResults: "{0} results found", // uses index placeholder {0}
        statusTypeXChar: "Type {0} or more characters for results"
    }, o);

    this.index = -1;

    // Create necessary elements

    this.container = this.container(input);

    this.ul = $.create("ul", {
        hidden: "hidden",
        role: "listbox",
        id: "awesomplete_list_" + this.count,
        inside: this.container,
        "aria-label": this.listLabel
    });

    this.status = $.create("span", {
        className: "visually-hidden",
        role: "status",
        "aria-live": "assertive",
        "aria-atomic": true,
        inside: this.container,
        textContent: ""  // live region should start empty. Only when the text is changed it will be read by the screen reader.
    });

    // Bind events

    this._events = {
        input: {
            "input": this.evaluate.bind(this),
            "blur": this.close.bind(this, { reason: "blur" }),
            "keydown": function(evt) {
                var c = evt.keyCode;

                // If the dropdown `ul` is in view, then act on keydown for the following keys:
                // Enter / Esc / Up / Down
                if(me.opened) {
                    if (c === 13 && me.selected) { // Enter
                        evt.preventDefault();
                        me.select(undefined, undefined, evt);
                    }
                    else if (c === 9 && me.selected && me.tabSelect) {
                        evt.preventDefault();
                        me.select(undefined, undefined, evt);
                    }
                    else if (c === 27) { // Esc
                        me.close({ reason: "esc" });
                    }
                    else if (c === 38 || c === 40) { // Down/Up arrow
                        evt.preventDefault();
                        me[c === 38? "previous" : "next"]();
                    }
                }
            }
        },
        form: {
            "submit": this.close.bind(this, { reason: "submit" })
        },
        ul: {
            // Prevent the default mousedowm, which ensures the input is not blurred.
            // The actual selection will happen on click. This also ensures dragging the
            // cursor away from the list item will cancel the selection
            "mousedown": function(evt) {
                evt.preventDefault();
            },
            // The click event is fired even if the corresponding mousedown event has called preventDefault
            "click": function(evt) {
                var li = evt.target;

                if (li !== this) {

                    while (li && !/li/i.test(li.nodeName)) {
                        li = li.parentNode;
                    }

                    if (li && evt.button === 0) {  // Only select on left click
                        evt.preventDefault();
                        me.select(li, evt.target, evt);
                    }
                }
            }
        }
    };

    $.bind(this.input, this._events.input);
    $.bind(this.input.form, this._events.form);
    $.bind(this.ul, this._events.ul);

    if (this.input.hasAttribute("list")) {
        this.list = "#" + this.input.getAttribute("list");
        this.input.removeAttribute("list");
    }
    else {
        this.list = this.input.getAttribute("data-list") || o.list || [];
    }

    _.all.push(this);
};

_.prototype = {
    set list(list) {
        if (Array.isArray(list)) {
            this._list = list;
        }
        else if (typeof list === "string" && list.indexOf(",") > -1) {
                this._list = list.split(/\s*,\s*/);
        }
        else { // Element or CSS selector
            list = $(list);

            if (list && list.children) {
                var items = [];
                slice.apply(list.children).forEach(function (el) {
                    if (!el.disabled) {
                        var text = el.textContent.trim();
                        var value = el.value || text;
                        var label = el.label || text;
                        if (value !== "") {
                            items.push({ label: label, value: value });
                        }
                    }
                });
                this._list = items;
            }
        }

        if (document.activeElement === this.input) {
            this.evaluate();
        }
    },

    get selected() {
        return this.index > -1;
    },

    get opened() {
        return this.isOpened;
    },

    close: function (o) {
        if (!this.opened) {
            return;
        }

        this.input.setAttribute("aria-expanded", "false");
        this.ul.setAttribute("hidden", "");
        this.isOpened = false;
        this.index = -1;

        this.status.setAttribute("hidden", "");

        $.fire(this.input, "awesomplete-close", o || {});
    },

    open: function () {
        this.input.setAttribute("aria-expanded", "true");
        this.ul.removeAttribute("hidden");
        this.isOpened = true;

        this.status.removeAttribute("hidden");

        if (this.autoFirst && this.index === -1) {
            this.goto(0);
        }

        $.fire(this.input, "awesomplete-open");
    },

    destroy: function() {
        //remove events from the input and its form
        $.unbind(this.input, this._events.input);
        $.unbind(this.input.form, this._events.form);

        // cleanup container if it was created by Awesomplete but leave it alone otherwise
        if (!this.options.container) {
            //move the input out of the awesomplete container and remove the container and its children
            var parentNode = this.container.parentNode;

            parentNode.insertBefore(this.input, this.container);
            parentNode.removeChild(this.container);
        }

        // remove autocomplete and aria attributes
        this.input.removeAttribute("autocomplete");
        this.input.removeAttribute("aria-autocomplete");
        this.input.removeAttribute("aria-expanded");
        this.input.removeAttribute("aria-owns");
        this.input.removeAttribute("role");

        //remove this awesomeplete instance from the global array of instances
        var indexOfAwesomplete = _.all.indexOf(this);

        if (indexOfAwesomplete !== -1) {
            _.all.splice(indexOfAwesomplete, 1);
        }
    },

    next: function () {
        var count = this.ul.children.length;
        this.goto(this.index < count - 1 ? this.index + 1 : (count ? 0 : -1) );
    },

    previous: function () {
        var count = this.ul.children.length;
        var pos = this.index - 1;

        this.goto(this.selected && pos !== -1 ? pos : count - 1);
    },

    // Should not be used, highlights specific item without any checks!
    goto: function (i) {
        var lis = this.ul.children;

        if (this.selected) {
            lis[this.index].setAttribute("aria-selected", "false");
        }

        this.index = i;

        if (i > -1 && lis.length > 0) {
            lis[i].setAttribute("aria-selected", "true");

            // fix: Turned off this status update.
            //        Screen readers Voiceover and Talkback won't read this status change.
            //        Narrator and NVDA do, but they already tell: 'X of Y (selected)'
            // this.status.textContent = lis[i].textContent + ", list item " + (i + 1) + " of " + lis.length;

            this.input.setAttribute("aria-activedescendant", this.ul.id + "_item_" + this.index);

            // scroll to highlighted element in case parent's height is fixed
            this.ul.scrollTop = lis[i].offsetTop - this.ul.clientHeight + lis[i].clientHeight;

            $.fire(this.input, "awesomplete-highlight", {
                text: this.suggestions[this.index]
            });
        }
    },

    select: function (selected, origin, originalEvent) {
        if (selected) {
            this.index = $.siblingIndex(selected);
        } else {
            selected = this.ul.children[this.index];
        }

        if (selected) {
            var suggestion = this.suggestions[this.index];

            var allowed = $.fire(this.input, "awesomplete-select", {
                text: suggestion,
                origin: origin || selected,
                originalEvent: originalEvent
            });

            if (allowed) {
                this.replace(suggestion);
                this.close({ reason: "select" });
                $.fire(this.input, "awesomplete-selectcomplete", {
                    text: suggestion,
                    originalEvent: originalEvent
                });
            }
        }
    },

    evaluate: function() {
        var me = this;
        var value = this.input.value;

        if (value.length >= this.minChars && this._list && this._list.length > 0) {
            this.index = -1;
            // Populate list with options that match
            this.ul.innerHTML = "";

            this.suggestions = this._list
                .map(function(item) {
                    return new Suggestion(me.data(item, value));
                })
                .filter(function(item) {
                    return me.filter(item, value);
                });

            if (this.sort !== false) {
                this.suggestions = this.suggestions.sort(this.sort);
            }

            this.suggestions = this.suggestions.slice(0, this.maxItems);

            this.suggestions.forEach(function(text, index) {
                    me.ul.appendChild(me.item(text, value, index));
                });

            if (this.ul.children.length === 0) {

                this.status.textContent = this.statusNoResults;

                this.close({ reason: "nomatches" });

            } else {
                this.open();

                this.status.textContent = this.statusXResults.replaceAll('{0}', this.ul.children.length); // N results found;
            }
        }
        else {

            this.close({ reason: "nomatches" });

            if (this.minChar <= 1 || value.length >= this.minChars) {
               this.status.textContent = this.statusNoResults;
            } else {
               this.status.textContent = this.statusTypeXChar.replaceAll('{0}', this.minChars); // Type N or more characters for results
            }

        }
    }
};

// Static methods/properties

_.all = [];

_.FILTER_CONTAINS = function (text, input) {
    return RegExp($.regExpEscape(input.trim()), "i").test(text);
};

_.FILTER_STARTSWITH = function (text, input) {
    return RegExp("^" + $.regExpEscape(input.trim()), "i").test(text);
};

_.SORT_BYLENGTH = function (a, b) {
    if (a.length !== b.length) {
        return a.length - b.length;
    }

    return a < b? -1 : 1;
};

_.CONTAINER = function (input) {
    return $.create("div", {
        className: "awesomplete",
        around: input
    });
}

_.ITEM = function (text, input, item_id) {
    var html = input.trim() === "" ? text : text.replace(RegExp($.regExpEscape(input.trim()), "gi"), "<mark>$&</mark>");
    return $.create("li", {
        innerHTML: html,
        "role": "option",
        "aria-selected": "false",
        "tabindex": '0', // for the Talkback screen reader
        "id": "awesomplete_list_" + this.count + "_item_" + item_id
    });
};

_.REPLACE = function (text) {
    this.input.value = text.value;
};

_.DATA = function (item/*, input*/) { return item; };

// Private functions

function Suggestion(data) {
    var o = Array.isArray(data)
      ? { label: data[0], value: data[1] }
      : typeof data === "object" && "label" in data && "value" in data ? data : { label: data, value: data };

    this.label = o.label || o.value;
    this.value = o.value;
}
Object.defineProperty(Suggestion.prototype = Object.create(String.prototype), "length", {
    get: function() { return this.label.length; }
});
Suggestion.prototype.toString = Suggestion.prototype.valueOf = function () {
    return "" + this.label;
};

function configure(instance, properties, o) {
    for (var i in properties) {
        var initial = properties[i],
            attrValue = instance.input.getAttribute("data-" + i.toLowerCase());

        if (typeof initial === "number") {
            instance[i] = parseInt(attrValue);
        }
        else if (initial === false) { // Boolean options must be false by default anyway
            instance[i] = attrValue !== null;
        }
        else if (initial instanceof Function) {
            instance[i] = null;
        }
        else {
            instance[i] = attrValue;
        }

        if (!instance[i] && instance[i] !== 0) {
            instance[i] = (i in o)? o[i] : initial;
        }
    }
}

// Helpers

var slice = Array.prototype.slice;

function $(expr, con) {
    return typeof expr === "string"? (con || document).querySelector(expr) : expr || null;
}

function $$(expr, con) {
    return slice.call((con || document).querySelectorAll(expr));
}

$.create = function(tag, o) {
    var element = document.createElement(tag);

    for (var i in o) {
        var val = o[i];

        if (i === "inside") {
            $(val).appendChild(element);
        }
        else if (i === "around") {
            var ref = $(val);
            ref.parentNode.insertBefore(element, ref);
            element.appendChild(ref);

            if (ref.getAttribute("autofocus") != null) {
                ref.focus();
            }
        }
        else if (i in element) {
            element[i] = val;
        }
        else {
            element.setAttribute(i, val);
        }
    }

    return element;
};

$.bind = function(element, o) {
    if (element) {
        for (var event in o) {
            var callback = o[event];

            event.split(/\s+/).forEach(function (event) {
                element.addEventListener(event, callback);
            });
        }
    }
};

$.unbind = function(element, o) {
    if (element) {
        for (var event in o) {
            var callback = o[event];

            event.split(/\s+/).forEach(function(event) {
                element.removeEventListener(event, callback);
            });
        }
    }
};

$.fire = function(target, type, properties) {
    var evt = document.createEvent("HTMLEvents");

    evt.initEvent(type, true, true );

    for (var j in properties) {
        evt[j] = properties[j];
    }

    return target.dispatchEvent(evt);
};

$.regExpEscape = function (s) {
    return s.replace(/[-\\^$*+?.()|[\]{}]/g, "\\$&");
};

$.siblingIndex = function (el) {
    /* eslint-disable no-cond-assign */
    for (var i = 0; el = el.previousElementSibling; i++);
    return i;
};

// Initialization

function init() {
    $$("input.awesomplete").forEach(function (input) {
        new _(input);
    });
}

// Make sure to export Awesomplete on self when in a browser
if (typeof self !== "undefined") {
    self.Awesomplete = _;
}

// Are we in a browser? Check for Document constructor
if (typeof Document !== "undefined") {
    // DOM already loaded?
    if (document.readyState !== "loading") {
        init();
    }
    else {
        // Wait for it
        document.addEventListener("DOMContentLoaded", init);
    }
}

_.$ = $;
_.$$ = $$;

// Expose Awesomplete as a CJS module
if (typeof module === "object" && module.exports) {
    module.exports = _;
}

return _;

}());