How to control when localstorage data expires?

Question

I’m storing some data on localstorage browser and would like to set an expiration date for that data, but I do not find a way to control when these data expire.

These data have some control over when they will be discarded?

When will the browser discard this data? If the user’s hard drive gets full, if it takes a few months? If the hard drive burns? hehe... forget the burning hard drive.

Answer 1

Apparently it is not possible to set expiration for data in localStorage.

Constant use of storage

Usually you will have a finite set of stored items and will update them when necessary, keeping the use more or less constant. In this scenario, you wouldn’t have to worry about the limit.

Solution to simulate data expiration

If you want to check whether the data is old, the best you can do is to store the date and time you created it and, when to retrieve it, check whether it is within acceptable time.

Example:

var object = {value: "value", timestamp: new Date().getTime()}
localStorage.setItem("key", JSON.stringify(object));

Then retrieve the item and check the date:

var object = JSON.parse(localStorage.getItem("key")),
    timestamp = object.timestamp,
    value = object.value;

verificarValidade(timestamp); 

Example source: response in Stackoverflow.com

Removing items that are no longer used

Problems start if you’re just adding new items indiscriminately.

If you know that some item will no longer be used, you can use the localStorage.removeItem(key) to free up storage space.

Also, if you have stored the date as indicated in the previous topic, you can also iterate over the stored items using length and key(n) and remove the old.

Temporary storage using sessionStorage

If the scope of the stored items does not need to last when the user closes the tab or the browser can also use the sessionStorage. He owns the same interface of localStorage, however, according to the specification, the data is removed after the user terminates the "session" or "context" of the browser.

Follow an example of use:

//save a value
sessionStorage.setItem("name", "Seu nome");

//retrieve item
var name = sessionStorage.getItem("name");

//get the key name for the first item
var key = sessionStorage.key(0);

//remove the key
sessionStorage.removeItem(key);

//check how many key-value pairs are present
var count = sessionStorage.length;

Example source here.

Answer 2

Although it varies according to the Browser, Localstorage has a limit size: https://stackoverflow.com/questions/3500713/html5-localstorage-size

I don’t know if there is any way to clean it automatically. I suspect it has to be manual anyway.

Answer 3

localstorage only deleting when it expires or the user cleans manually.

localStorage will keep the data recorded until it is removed directly, you can close the browser, restart the computer and the data will still be there. -- Source

The way to validate is equal to the cookie, if it does not exist is because it has been deleted.

Answer 4

There really is no expiration date for this data, what you can do is control by javascript when the user accesses the application you check if it is time to expire the data, and do the reload, or just remove the information.

You can Jstorage which has the setTTL(key, ttl) method which in turn uses setTimeout, but if you want to use this "expiration" equal cookie would have to be developed.