Find out how to Override Strategies in localStorage? | by Sabesan Sathananthan

Use localStorage with JavaScript.

Picture by Lia Trevarthen on Unsplash

I usually wish to rewrite localStorage to implement a sure perform. What are the strategies to rewrite the strategies in localStorage? There are a lot of builders who wish to rewrite the strategies in localStorageto appreciate the expiration time of the important thing, or to observe the learn and write of the important thing. So what are the strategies to override the strategies in localStorage. That is my forty third Medium article.

Many builders like the thought of ​​rewriting, first maintaining the unique technique after which rewriting the tactic instantly on localStorage like under.

Nonetheless, this fashion of writing shouldn’t be overriding the tactic setItem(), however so as to add a setItem attribute to localStorage. When the worth attribute of the tactic is said, the native setItem() technique is overwritten.

I haven’t examined it an excessive amount of, however in some browsers, this attribute will probably be ignored and inflicting our rewriting to fail.

If we glance intently, setItem and getItem are inherited from Storage __proto__ pseudo property.

Then we instantly override the above localStorage.__proto__ technique.

This implements the actual override of the setItem() technique.

However there may be nonetheless an issue right here. Each localStorage and sessionStorage inherit from Storage. After rewriting the properties or strategies on localStorage.__proto__, the strategies in sessionStorage are additionally rewritten.

We don’t instantly modify the tactic of localStorage itself, however wrap a layer on the surface, after which use localStorage to appreciate the storage perform on the backside layer.

On this method, the diploma of freedom is comparatively greater, and there’s no compatibility downside in Part 1. Solely the title used has modified and the properties and strategies in localStorage are utterly blocked.

If you wish to use a customized object with out the pack then you should implement all of the properties and strategies. It isn’t attainable to mock a technique alone just like the above.

Use Object.definePropertyor Proxyequal to utterly overriding the localStorage variable. Higher than Part 3 in that the title has not modified.

4.1 Direct protection, no impact

For those who use the next technique to cowl instantly, it would haven’t any impact.

window.localStorage = Object.create(null);  console.log(window.localStorage); //nonetheless native

We get the property descriptor of localStorage by means of Object.getOwnPropertyDescriptor. It may be discovered that there is no such thing as a writable: true attribute, which implies that localStorage shouldn’t be instantly writable.

4.2 Overriding with Object.defineProperty

Since there is no such thing as a writableattribute, we’ll add one to it. We are able to override localStorage with Object.defineProperty.

However you may’t use the above writing technique with one layer outdoors. For those who instantly give the above myLocalStorage to localStorage then it would generate infinite recursion (to keep away from deceptive, the improper writing technique won’t be written right here).

I’ve made a backup of localStorage right here. For those who want a local technique then you may also function it.

On this article, we don’t particularly implement a perform similar to setting the expiration time. However speak about the way to rewrite localStorage or the strategies in it from one other perspective.

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