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Use localStorage with JavaScript.
I usually wish to rewrite localStorage to implement a sure perform. What are the strategies to rewrite the strategies in localStorage? There are various builders who wish to rewrite the strategies in localStorageto comprehend 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 conserving the unique technique after which rewriting the tactic immediately on localStorage like beneath.
Nonetheless, this manner 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 asserted, the native setItem() technique is overwritten.
I haven’t examined it an excessive amount of, however in some browsers, this attribute shall be ignored and inflicting our rewriting to fail.
If we glance intently, setItem and getItem are inherited from Storage __proto__ pseudo property.
Then we immediately 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 immediately modify the tactic of localStorage itself, however wrap a layer on the surface, after which use localStorage to comprehend the storage perform on the backside layer.
On this manner, the diploma of freedom is comparatively increased, and there’s no compatibility drawback in Part 1. Solely the title 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 title has not modified.
4.1 Direct protection, no impact
For those who use the next technique to cowl immediately, it’ll don’t have 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 signifies that localStorage shouldn’t be immediately writable.
4.2 Overriding with Object.defineProperty
Since there is no such thing as a writableattribute, we’ll add one to it. We will override localStorage with Object.defineProperty.
However you possibly can’t use the above writing technique with one layer outdoors. For those who immediately give the above myLocalStorage to localStorage then it’ll generate infinite recursion (to keep away from deceptive, the incorrect writing technique is not going to be written right here).
I’ve made a backup of localStorage right here. For those who want a local technique then you can even function it.
On this article, we don’t particularly implement a perform similar to setting the expiration time. However discuss methods to rewrite localStorage or the strategies in it from one other perspective.
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