For Loop..not looping throught all localStorage keys

Question

I'm trying to loop throught all my current localStorage items, but I cannot get to make it work properly, always last item is missing, not sure what else it could be.

function sortObject() {

    for(let i = 0; i < localStorage.length; i++) {
        if(localStorage.getItem(i) !== null) {

        let retrieveData = localStorage.getItem(i);
        let retrieveObject = JSON.parse(retrieveData);
        
        console.log(retrieveObject.index);
        }
    } 
}

Output: 
SortObject()
1
undefined