tes

(function result() {
    function binary(a, b, operation) {
        const array = [];
        for (let index = 0; index <= 1; index++) {
            const result = operation(a[index], b[index]);
            array.push(result);
        }

        return array;
    }

    function product(a, b) {
        return a * b;
    }

    function add(a, b) {
        return binary(a, b, (a, b) => a + b);
    }

    function multiply(a, b) {
        return binary(a, b, product);
    }

    function length(a) {
        return Math.sqrt(Math.pow(a[0], 2) + Math.pow(a[1], 2));
    }

    function dot(a, b) {
        return binary(a, b, product).reduce((prev, curr) => prev + curr, 0);
    }

    function cross(a, b) {
        return a[0] * b[1] - a[1] * b[0];
    }

    return {
        'add': add,
        'multiply': multiply,
        'length': length,
        'dot': dot,
        'cross': cross,
    };
})()