vectors

(() => {
    let add = (v1, v2) => [v1[0] + v2[0], v1[1] + v2[1]];
    let multiply = (v1, sc) => [v1[0] * sc, v1[1] * sc];
    let length = (v1) => Math.sqrt(Math.pow(v1[0], 2) + Math.pow(v1[1], 2));
    let dot = (v1, v2) => v1[0] * v2[0] + v1[1] * v2[1];
    let cross = (v1, v2) => v1[0] * v2[1] - v1[1] * v2[0];

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