Storage JS Fundamentals

function storage(arr) {
    let store = new Map();

    for (let line of arr) {
        let tokens = line.split(' ');
        let product = tokens[0];
        let quantity = Number(tokens[1]);

        if (store.has(product)) {
            let currentQuantity = store.get(product); // запазваме текущото количество
            let newQuantity = currentQuantity += quantity;
            store.set(product, newQuantity);
        } else {
            store.set(product, +quantity);
        }
    }
    for (let line of store) {
        console.log(`${line[0]} -> ${line[1]}`);
    }
}