howsum.js

const howSum = (targetSum, numbers, memo = new Map()) => {
    const key = `${targetSum}`;
    if (memo.has(key)) return memo.get(key);
    if (targetSum === 0) return [];
    if (targetSum <= 0) return null;
    for (let num of numbers) {
        const remainder = targetSum - num;
        const res = howSum(remainder, numbers, memo);
        if (res === null) continue;
        res.push(num);
        memo.set(key, res);
        return memo.get(key);
    }
    memo.set(key, null);
    return null;
};
console.log(howSum(7, [3,4]));
console.log(howSum(7, [3, 4, 5, 7])); //returns 3,4 or 7
console.log(howSum(7, [2, 4]));// returns null
console.log(howSum(300, [7, 14]));
console.log(howSum(301, [1, 2, 3]));