problem 2_3 - mid exam

function solve(input) {

    let oldFavoriteGenres = input.shift().split(' | ');
    let line = input.shift();

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

        switch (command) {
            case 'Join':
                toJoin(oldFavoriteGenres, item);
                break;
            case 'Drop':
                drop(oldFavoriteGenres, item);
                break;
            case 'Replace':
                replace(oldFavoriteGenres, item, newItem);
                break;
            default:
                break;
        }
        line = input.shift();
    }


    console.log(oldFavoriteGenres.join(' '));

    function toJoin(list, item) {
        if (list.includes(item) == false) {
            list.push(item);
        }
    }

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

    }

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

}