check the previously generated basket url for out of stock products when building the site basket

appCheckBasket.js

/*
* app -> site basket item validation
* alert user if sku's missing, presumed out of stock
/

/*
* example of multi with missing sku: ?log=22&ex=co_wizr-shopcart&mode=addmul&param1=bulk&qtylist=2&itemlist=azz1368510520&qtylist=1&itemlist=azz2199912835&itemlist=azz111111&itemlist=azz111112
* example of single sku ?log=22&ex=co_wizr-shopcart&mode=addmul&param1=bulk&qtylist=2&itemlist=azz1368510520&qtylist=1&itemlist=azz2199912835
* example of multi sku ?log=22&ex=co_wizr-shopcart&mode=addmul&param1=bulk&qtylist=1&itemlist=azz1368510520&
*/

/*
* first we need to check that we're in the shopcart
*/


$( document ).ready(function(){

    var _wfshop = false,
        _wfitems = false;

    if ( $('.workflow-shopcart').length ) {
        _wfshop = true;
    }

    /*
    * now we need to check if this is app -> site flow
    */

    if (window.location.href.indexOf("itemlist") > -1) {
        _wfitems = true;
    }

    /*
    * if both are true, we know what we're dealing with
    */

    if ( _wfshop && _wfitems ) {
        compareItems();
    }

    /*
    * now we need to compare the items passed in the url
    * with those that have actually added to basket
    * any that are missing presume out of stock
    * display a warning for the user
    */

    function compareItems() {

        /*
        * get skus from url
        */

        var itemArr = location.search.substring(1).split( '&' ).reduce(function( pre, cur ){
        var _param = cur.split( '=' );
        
        if ( _param[0] === 'itemlist' ) pre.push( _param[1] );

            return pre;
        },[]);

        /*
        * array of skus from url itemArr, thanks James!
        */

        /*
        * get skus from basket
        */

        var _basket = _orditemJSON(),
            basketArr = [],
            missingSkus = [];

        var _basketArr = $.each(_basket, function( index ){
            basketArr.push( this.sku );
        });

        /*
        * check if string of basket skus matches array of url skus (itemArr & basketArr)
        * return any not matching
        */

        $.grep( itemArr, function( el ) {
            if ( $.inArray( el, basketArr ) == -1 ) missingSkus.push( el );
        });

        /*
        * alert the user in nice big bold red text :)
        */

        $( "<div class=\"row\"><strong class=\"classRed\" style=\"text-align:center;display:block;\">The following items are now out of stock, and could not be added to the basket: " + missingSkus + "</strong>" ).insertAfter( ".js-header-promobasket-2-div" );

    }

});