cross_product.js

function leviCivita(i, j, k) {
  let d1 = i - j;
  let d2 = j - k;
  let d3 = k - i;
  return (d1 * d2 * d3) / 2;
}

function cross(v1, v2) {
  if (v1.length !== v2.length !== 3) {
    return new Error("Only 3D vectors are supported");
  }
  let result = [0, 0, 0];
  for (var i = 0; i < 3; i++) {
    for (var j = 0; j < 3; j++) {
      for (var k = 0; k < 3; k++) {
        result[i] += leviCivita(i, j, k) * v1[j] * v2[k];
      }
    }
  } 
  return result;
}