function arrayPreviousLess(nums) {
    //  write code here.
    return nums.map((num, index) => {
        let lower = -1;
        for(let i=0; i < index; i++) {
            if(nums[i] < num) {
                lower = nums[i];
            }
        }
        return lower;
    })
}



/**
* 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]);
    });
});