function arrayPreviousLess(nums) {
    //  write code here.
    //Initialize the array, the first value will always be -1
    const returnArray = [-1];
    
    //loop through the array, starting on the 2nd value
    for( i = 1; i < nums.length; i++ ){
        if (nums[i] > nums[i-1]){
            returnArray.push(nums[i-1]);
        }else{
            returnArray.push(-1);
        }
    }
    
    return returnArray;
}



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