function adjacentElementsProduct(nums) {
  if (nums.length < 2) return nums[0];
  let product = nums[0] * nums[1];
  const lastIndex = nums.length - 1;
  for (let i = 1; i < lastIndex; i++) {
    if (nums[i] * nums[i + 1] > product) {
      product = nums[i] * nums[i + 1];
    }
  }
  return product;
}



/**
* Test Suite 
*/
describe('adjacentElementsProduct()', () => {
    it('returns largest product of adjacent values', () => {
        // arrange
        const nums = [3, 6, -2, -5, 7, 3];
        
        // act
        const result = adjacentElementsProduct(nums);

        // log
        console.log("result: ", result);
        
        // assert
        expect(result).toBe(21);
    });
});