Questions-and-Answers/media/uikit-v2/js/core/scrollspy.js

/*! UIkit 2.27.4 | http://www.getuikit.com | (c) 2014 YOOtheme | MIT License */
(function(UI) {

    "use strict";

    var $win           = UI.$win,
        $doc           = UI.$doc,
        scrollspies    = [],
        checkScrollSpy = function() {
            for(var i=0; i < scrollspies.length; i++) {
                window.requestAnimationFrame.apply(window, [scrollspies[i].check]);
            }
        };

    UI.component('scrollspy', {

        defaults: {
            target     : false,
            cls        : 'uk-scrollspy-inview',
            initcls    : 'uk-scrollspy-init-inview',
            topoffset  : 0,
            leftoffset : 0,
            repeat     : false,
            delay      : 0
        },

        boot: function() {

            // listen to scroll and resize
            $doc.on('scrolling.uk.document', checkScrollSpy);
            $win.on('load resize orientationchange', UI.Utils.debounce(checkScrollSpy, 50));

            // init code
            UI.ready(function(context) {

                UI.$('[data-uk-scrollspy]', context).each(function() {

                    var element = UI.$(this);

                    if (!element.data('scrollspy')) {
                        var obj = UI.scrollspy(element, UI.Utils.options(element.attr('data-uk-scrollspy')));
                    }
                });
            });
        },

        init: function() {

            var $this = this, inviewstate, initinview, togglecls = this.options.cls.split(/,/), fn = function(){

                var elements     = $this.options.target ? $this.element.find($this.options.target) : $this.element,
                    delayIdx     = elements.length === 1 ? 1 : 0,
                    toggleclsIdx = 0;

                elements.each(function(idx){

                    var element     = UI.$(this),
                        inviewstate = element.data('inviewstate'),
                        inview      = UI.Utils.isInView(element, $this.options),
                        toggle      = element.attr('data-uk-scrollspy-cls') || togglecls[toggleclsIdx].trim();

                    if (inview && !inviewstate && !element.data('scrollspy-idle')) {

                        if (!initinview) {
                            element.addClass($this.options.initcls);
                            $this.offset = element.offset();
                            initinview = true;

                            element.trigger('init.uk.scrollspy');
                        }

                        element.data('scrollspy-idle', setTimeout(function(){

                            element.addClass('uk-scrollspy-inview').toggleClass(toggle).width();
                            element.trigger('inview.uk.scrollspy');

                            element.data('scrollspy-idle', false);
                            element.data('inviewstate', true);

                        }, $this.options.delay * delayIdx));

                        delayIdx++;
                    }

                    if (!inview && inviewstate && $this.options.repeat) {

                        if (element.data('scrollspy-idle')) {
                            clearTimeout(element.data('scrollspy-idle'));
                            element.data('scrollspy-idle', false);
                        }

                        element.removeClass('uk-scrollspy-inview').toggleClass(toggle);
                        element.data('inviewstate', false);

                        element.trigger('outview.uk.scrollspy');
                    }

                    toggleclsIdx = togglecls[toggleclsIdx + 1] ? (toggleclsIdx + 1) : 0;

                });
            };

            fn();

            this.check = fn;

            scrollspies.push(this);
        }
    });


    var scrollspynavs = [],
        checkScrollSpyNavs = function() {
            for(var i=0; i < scrollspynavs.length; i++) {
                window.requestAnimationFrame.apply(window, [scrollspynavs[i].check]);
            }
        };

    UI.component('scrollspynav', {

        defaults: {
            cls          : 'uk-active',
            closest      : false,
            topoffset    : 0,
            leftoffset   : 0,
            smoothscroll : false
        },

        boot: function() {

            // listen to scroll and resize
            $doc.on('scrolling.uk.document', checkScrollSpyNavs);
            $win.on('resize orientationchange', UI.Utils.debounce(checkScrollSpyNavs, 50));

            // init code
            UI.ready(function(context) {

                UI.$('[data-uk-scrollspy-nav]', context).each(function() {

                    var element = UI.$(this);

                    if (!element.data('scrollspynav')) {
                        var obj = UI.scrollspynav(element, UI.Utils.options(element.attr('data-uk-scrollspy-nav')));
                    }
                });
            });
        },

        init: function() {

            var ids     = [],
                links   = this.find("a[href^='#']").each(function(){ if(this.getAttribute('href').trim()!=='#') ids.push(this.getAttribute('href')); }),
                targets = UI.$(ids.join(",")),

                clsActive  = this.options.cls,
                clsClosest = this.options.closest || this.options.closest;

            var $this = this, inviews, fn = function(){

                inviews = [];

                for (var i=0 ; i < targets.length ; i++) {
                    if (UI.Utils.isInView(targets.eq(i), $this.options)) {
                        inviews.push(targets.eq(i));
                    }
                }

                if (inviews.length) {

                    var navitems,
                        scrollTop = $win.scrollTop(),
                        target = (function(){
                            for(var i=0; i< inviews.length;i++){
                                if (inviews[i].offset().top - $this.options.topoffset >= scrollTop){
                                    return inviews[i];
                                }
                            }
                        })();

                    if (!target) return;

                    if ($this.options.closest) {
                        links.blur().closest(clsClosest).removeClass(clsActive);
                        navitems = links.filter("a[href='#"+target.attr('id')+"']").closest(clsClosest).addClass(clsActive);
                    } else {
                        navitems = links.removeClass(clsActive).filter("a[href='#"+target.attr("id")+"']").addClass(clsActive);
                    }

                    $this.element.trigger('inview.uk.scrollspynav', [target, navitems]);
                }
            };

            if (this.options.smoothscroll && UI.smoothScroll) {
                links.each(function(){
                    UI.smoothScroll(this, $this.options.smoothscroll);
                });
            }

            fn();

            this.element.data('scrollspynav', this);

            this.check = fn;
            scrollspynavs.push(this);

        }
    });

})(UIkit2);