Describe: luhnAlgorithm()
Test 1: "It should return 0 if the number is 0." Code: const number = 0; luhnAlgorithm(number); Expected Output: 0
Test 2: "It should double the digit if the number is not 0." Code: const number = 1; luhnAlgorithm(number); Expected Output: 2
Test 3: "It should take multiple digits and double all digits separately." Code: const number = 123; luhnAlgorithm(number); Expected Output: 246
Test 4: Code: Expected Output: