function shopingList(input) {

    let groceries = input.shift().split('!');
    let line = input.shift();

    while (line != 'Go Shopping!') {
        let [command, item, newItem] = line.split(' ');

        switch (command) {
            case 'Urgent':
                urgent(groceries, item);
                break;
            case 'Unnecessary':
                unnecessery(groceries, item);
                break;
            case 'Correct':
                correct(groceries, item, newItem);
                break;
            case 'Rearrange':
                rearrange(groceries, item);
                break;
            default: break; // needs to include default case for invalid command('Gosho'), otherwise will not break
        }
        line = input.shift();
    }

    console.log(groceries.join(', '));

    function urgent(list, item) {
        if (list.includes(item) == false) {
            list.unshift(item);
        }
    }

    function unnecessery(list, item) {
        if (list.includes(item) == true) {
            let index = list.indexOf(item);
            list.splice(index, 1);
        }
    }

    function correct(list, item, newItem) {
        if (list.includes(item) == true) {
            let index = list.indexOf(item);
            list[index] = newItem;
        }
    }

    function rearrange(list, item) {
        if (list.includes(item) == true) {
            let index = list.indexOf(item);
            // splice and push can not be chained, otherwise will not include removed item at end of list
            list.splice(index, 1);
            list.push(item);
        }
    }
}

;-)