Merge ecdc7bd172 into ca3d16dcce

src/algorithms/sets/cartesian-product/__test__/cartesianProduct.test.js

@@ -16,4 +16,12 @@ describe('cartesianProduct', () => {
     expect(product1).toEqual([[1, 1]]);
     expect(product2).toEqual([[1, 3], [1, 5], [2, 3], [2, 5]]);
   });
+
+  it('should return an empty set if one or both of the source is empty', () => {
+    const product1 = cartesianProduct([], [1, 2, 3]);
+    const product2 = cartesianProduct([], []);
+
+    expect(product1).toEqual([]);
+    expect(product2).toEqual([]);
+  });
 });

src/algorithms/sets/cartesian-product/cartesianProduct.js

@@ -5,14 +5,17 @@
  * @return {*[]}
  */
 export default function cartesianProduct(setA, setB) {
-  // Check if input sets are not empty.
+  // Check if input sets are not non-arrays.
   // Otherwise return null since we can't generate Cartesian Product out of them.
-  if (!setA || !setB || !setA.length || !setB.length) {
+  if (!setA || !setB) {
     return null;
   }
 
   // Init product set.
   const product = [];
+  if (!setA.length || !setB.length) {
+    return product;
+  }
 
   // Now, let's go through all elements of a first and second set and form all possible pairs.
   for (let indexA = 0; indexA < setA.length; indexA += 1) {