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Use localStorage with JavaScript.
I typically need to rewrite localStorage to implement a sure perform. What are the strategies to rewrite the strategies in localStorage? There are lots of builders who need to rewrite the strategies in localStorageto appreciate the expiration time of the important thing, or to watch 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 methodology after which rewriting the strategy straight on localStorage like under.
Nevertheless, this manner of writing isn’t overriding the strategy setItem(), however so as to add a setItem attribute to localStorage. When the worth attribute of the strategy is said, the native setItem() methodology is overwritten.
I haven’t examined it an excessive amount of, however in some browsers, this attribute might be ignored and inflicting our rewriting to fail.
If we glance carefully, setItem and getItem are inherited from Storage __proto__ pseudo property.
Then we straight override the above localStorage.__proto__ methodology.
This implements the true override of the setItem() methodology.
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 straight modify the strategy 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 approach, 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 it is advisable to implement all of the properties and strategies. It’s not attainable to mock a technique 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
In the event you use the next methodology to cowl straight, it’s going to haven’t any impact.
window.localStorage = Object.create(null); console.log(window.localStorage); //nonetheless native
We get the property descriptor of localStorage via Object.getOwnPropertyDescriptor. It may be discovered that there isn’t a writable: true attribute, which signifies that localStorage isn’t straight writable.
4.2 Overriding with Object.defineProperty
Since there isn’t a writableattribute, we’ll add one to it. We will override localStorage with Object.defineProperty.
However you possibly can’t use the above writing methodology with one layer outdoors. In the event you straight give the above myLocalStorage to localStorage then it’s going to generate infinite recursion (to keep away from deceptive, the flawed writing methodology won’t be written right here).
I’ve made a backup of localStorage right here. In the event you want a local methodology then you can too function it.
On this article, we don’t particularly implement a perform corresponding to setting the expiration time. However discuss easy methods to rewrite localStorage or the strategies in it from one other perspective.
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