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
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 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.
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
However you possibly can’t use the above writing technique with one layer outdoors. For those who immediately give the above
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.