Use localStorage with JavaScript.
I typically need to rewrite localStorage to implement a sure operate. What are the strategies to rewrite the strategies in localStorage? There are numerous builders who need to rewrite the strategies in localStorageto comprehend 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 concept of ​​rewriting, first holding the unique technique after which rewriting the tactic instantly on localStorage like beneath.
Nevertheless, this fashion of writing will not 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 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 comprehend the storage operate on the backside layer.
On this manner, the diploma of freedom is comparatively larger, and there’s no compatibility downside in Part 1. Solely the identify 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 it’s essential implement all of the properties and strategies. It’s not potential 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 identify has not modified.
4.1 Direct protection, no impact
In the event you use the next technique to cowl instantly, it should 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 isn’t any writable: true attribute, which implies that localStorage will not be instantly writable.
4.2 Overriding with Object.defineProperty
Since there isn’t any writableattribute, we are going to add one to it. We are able to override localStorage with Object.defineProperty.
However you possibly can’t use the above writing technique with one layer exterior. In the event you instantly give the above myLocalStorage to localStorage then it should generate infinite recursion (to keep away from deceptive, the fallacious writing technique won’t be written right here).
I’ve made a backup of localStorage right here. In the event you want a local technique then you too can function it.
On this article, we don’t particularly implement a operate equivalent 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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