map()

// Storage
// Write a function that takes a certain number of items and their quantity. If the same item appears more than once,
// add the new amount to the existing one. In the end, print all the items and their amount without sorting them. The
// input comes as an array of strings. Try using a Map().

function solve(arr) {

    let map = new Map();

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

        if(!map.has(product)) {
            map.set(product, +quantity);
        } else {
            let currQuantity = map.get(product)
            let newQuantity = currQuantity += quantity;
            map.set(product, newQuantity);
        }
    }

    for (let kvp of map) {
        console.log(`${kvp[0]} -> ${kvp[1]}`);
    }

}