Use localStorage with JavaScript.
I usually wish to rewrite localStorage to implement a sure operate. What are the strategies to rewrite the strategies in localStorage? There are numerous builders who wish to rewrite the strategies in localStorageto understand 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 preserving the unique technique after which rewriting the tactic straight on localStorage like under.
Nevertheless, this manner of writing just isn’t 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 can be ignored and inflicting our rewriting to fail.
If we glance intently, setItem and getItem are inherited from Storage __proto__ pseudo property.
Then we straight 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 straight modify the tactic of localStorage itself, however wrap a layer on the skin, after which use localStorage to understand the storage operate on the backside layer.
On this means, 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 utterly blocked.
If you wish to use a customized object with out the pack then it is advisable implement all of the properties and strategies. It’s not attainable to mock a way 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
When you use the next technique to cowl straight, it’s 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 isn’t any writable: true attribute, which implies that localStorage just isn’t straight writable.
4.2 Overriding with Object.defineProperty
Since there isn’t any writableattribute, we are going to add one to it. We will override localStorage with Object.defineProperty.
However you’ll be able to’t use the above writing technique with one layer exterior. When you straight give the above myLocalStorage to localStorage then it’s going to generate infinite recursion (to keep away from deceptive, the flawed writing technique won’t be written right here).
I’ve made a backup of localStorage right here. When you want a local technique then you may as well function it.
On this article, we don’t particularly implement a operate reminiscent of setting the expiration time. However speak about tips on how to rewrite localStorage or the strategies in it from one other perspective.
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