function arrayPreviousLess(nums) {
    let result = [];
    for (let i = nums.length - 1, j = i - 1; i >= 0; i--, j--) {
        if (nums[j] < nums[i]) {
            result.unshift(nums[j]);
        } else {
            result.unshift(-1);
        }
    }
    return result;
}



/**
* Test Suite 
*/
describe('arrayPreviousLess()', () => {
    it('shift previous postions from the left to a smaller value or store -1', () => {
        // arrange
        const nums = [3, 5, 2, 4, 5];
        
        // act
        const result = arrayPreviousLess(nums);

        // log
        console.log("result: ", result);
        
        // assert
        expect(result).toEqual([-1, 3, -1, 2, 4]);
    });
});