HomeSoftware EngineeringThe way to Override Strategies in localStorage? | by Sabesan Sathananthan |...

The way to Override Strategies in localStorage? | by Sabesan Sathananthan | Sep, 2022


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 protecting the unique technique after which rewriting the strategy instantly on localStorage like beneath.

Nevertheless, this manner of writing will not be overriding the strategy setItem(), however so as to add a setItem attribute to localStorage. When the worth attribute of the strategy is asserted, 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 true 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 strategy of localStorage itself, however wrap a layer on the skin, after which use localStorage to appreciate the storage perform on the backside layer.

On this manner, the diploma of freedom is comparatively increased, and there’s no compatibility downside in Part 1. Solely the identify used has modified and the properties and strategies in localStorage are fully blocked.

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

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

4.1 Direct protection, no impact

When you use the next technique to cowl instantly, it is going to don’t have any impact.

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

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

4.2 Overriding with Object.defineProperty

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

However you may’t use the above writing technique with one layer exterior. When you instantly give the above myLocalStorage to localStorage then it is going to generate infinite recursion (to keep away from deceptive, the fallacious writing technique is not going to be written right here).

I’ve made a backup of localStorage right here. When you want a local technique then you can even function it.

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

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