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 maintaining the unique technique after which rewriting the tactic instantly on localStorage like under.
Nonetheless, this fashion 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 said, 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
This implements the actual override of the
However there may be nonetheless an issue right here. Each
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 appreciate the storage perform on the backside layer.
On this method, the diploma of freedom is comparatively greater, and there’s no compatibility downside 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 you should implement all of the properties and strategies. It isn’t attainable to mock a technique alone just like the above.
Proxyequal to utterly 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 instantly, it would haven’t 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 implies that
localStorage shouldn’t be instantly writable.
4.2 Overriding with Object.defineProperty
Since there is no such thing as a
writableattribute, we’ll add one to it. We are able to override
However you may’t use the above writing technique with one layer outdoors. For those who instantly give the above
localStorage then it would generate infinite recursion (to keep away from deceptive, the improper writing technique won’t be written right here).
I’ve made a backup of
localStorage right here. For those who want a local technique then you may also function it.
On this article, we don’t particularly implement a perform similar to setting the expiration time. However speak about the way to rewrite
localStorage or the strategies in it from one other perspective.