const alternatingSums = array => [
    array.reduce((acc, cur, ind) => !(ind % 2) ? acc + cur : acc, 0),
    array.reduce((acc, cur, ind) =>   ind % 2  ? acc + cur : acc, 0)
];

/**
* Test Suite 
*/
describe('alternatingSums()', () => {
    it('returns alternating sums of even and odd', () => {
        // arrange
        const nums = [50, 60, 60, 45, 70];
        
        // act
        const result = alternatingSums(nums);

        // log
        console.log("result: ", result);
        
        // assert
        expect(result).toEqual([180, 105]);
    });
});