warehouse.js

class Warehouse {
    constructor(catalogue) {
        this.catalogue = catalogue;
    }

    receive(batch) {
        const received = batch.cds[0];
        let cd = this.catalogue.search(received.title, received.artist);
        if (cd == null) {
            cd = this.catalogue.add(received);
        }
        cd.addStock(received.copies);
    }
}