I typically wish to rewrite
localStorage to implement a sure operate. What are the strategies to rewrite the strategies in
localStorage? There are a lot of builders who wish to rewrite the strategies in
localStorageto understand 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 conserving the unique technique after which rewriting the tactic immediately on localStorage like under.
Nonetheless, this fashion 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 said, 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 carefully, setItem and getItem are inherited from Storage
__proto__ pseudo property.
Then we immediately override the above
This implements the true 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 immediately 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 method, the diploma of freedom is comparatively greater, 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 you want to implement all of the properties and strategies. It isn’t doable to mock a way alone just like the above.
Proxyequal to fully overriding the
localStorage variable. Higher than Part 3 in that the title has not modified.
4.1 Direct protection, no impact
In the event you use the next technique to cowl immediately, it is going to 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 isn’t a writable: true attribute, which signifies that
localStorage just isn’t immediately writable.
4.2 Overriding with Object.defineProperty
Since there isn’t a
writableattribute, we are going to add one to it. We will override
However you may’t use the above writing technique with one layer outdoors. In the event you immediately give the above
localStorage then it is going to generate infinite recursion (to keep away from deceptive, the unsuitable 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 can even function it.
On this article, we don’t particularly implement a operate resembling setting the expiration time. However discuss easy methods to rewrite
localStorage or the strategies in it from one other perspective.