Function update

javascript/0043-multiply-strings.js:44–57

(num1, i, num2, j, buffer)

};

var update = (num1, i, num2, j, buffer) => {
    const curPos = i + j;
    const prevPos = curPos + 1;

    const carry = buffer[prevPos];
    const product = getProduct(num1, i, num2, j);
    const sum = carry + product;

    const remainder = sum % 10;
    const value = (sum - remainder) / 10;

    buffer[prevPos] = remainder; /* Space O(N + M) */
    buffer[curPos] += value; /* Space O(N + M) */
};

var getProduct = (num1, i, num2, j) => {
    const [iNum, jNum] = [Number(num1[i]), Number(num2[j])];