reordering the localstorage after deletion of an entry

Question

Is there a way of changing a key in a localstorage? For example, if I have a key set to "4" and value of "myvalue" and I'd like to change the key to 3. What would the process be?

Would I have to getItem first and then Setitem with an index-1?

I want to call a function on page unload that reorders the keys and sets 3 to 2 (reindex it).

Ideas would be appreciated

do you want to exchange them or simple replace 2 and delete 3? — iLuvLogix, Feb 08 '19 at 12:54

Amsvartner · Answer 1 · 2019-02-08T13:32:19.290

2

You'll first have to set the new value, before deleting the old one. Like this:

function changeKey(oldKey, newKey) {
    localStorage.setItem(newKey, localStorage.getItem(oldKey));
    localStorage.removeItem(oldKey);
}

I would suggest that you do not use the localStorage as an array like that though, but instead use a single localStorage item to store your array:

var myArray = [ { a : 1 }, { b : 2 } ];

localStorage.setItem("myArray", JSON.stringify(myArray));

Then whenever you want to manipulate the array, you can do it like this, and the array indexes will update automatically:

var myArray = JSON.parse(localStorage.getItem("myArray")); // Fetching the array

myArray.splice(myIndex, 1); // Removing an item with index 'myIndex';

localStorage.setItem("myArray", JSON.stringify(myArray)); // Storing the changes

edited Feb 08 '19 at 13:32

answered Feb 08 '19 at 12:48

Amsvartner

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is there a way of looping through the whole Local storage? perhaps a for loop that runs till storage.length? – Subjugation Feb 08 '19 at 12:50
1

More on that... https://stackoverflow.com/questions/17745292/how-to-retrieve-all-localstorage-items-without-knowing-the-keys-in-advance – Cat Feb 08 '19 at 12:55
Good point, @Cat. Looping through localStorage might also be needlessly complicated; I've updated my original answer with a suggested alternative approach – Amsvartner Feb 11 '19 at 09:14

iLuvLogix · Answer 2 · 2019-02-08T12:55:44.903

1

General approach:

function changeKeyforStorageItem(oldKey, newKey) {
   let myValue = localStorage.getItem(oldKey);
   localStorage.removeItem(oldKey);
   localStorage.setItem(newKey, myValue);
}

or :

 function changeKeyforStorageItem(oldKey, newKey) {
    localStorage.setItem(newKey, localStorage.getItem(oldKey));
    localStorage.removeItem(oldKey);
 }

edited Feb 08 '19 at 12:55

answered Feb 08 '19 at 12:43

iLuvLogix

5,920
3
26
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reordering the localstorage after deletion of an entry

2 Answers2