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 appreciate 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 concept of rewriting, first holding the unique methodology after which rewriting the tactic instantly 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 said, the native
setItem() methodology is overwritten.
I haven’t examined it an excessive amount of, however in some browsers, this attribute will likely be ignored and inflicting our rewriting to fail.
If we glance carefully, 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 skin, after which use
localStorage to appreciate the storage operate on the backside layer.
On this method, 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 you have to implement all of the properties and strategies. It’s not doable 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
Should you use the next methodology to cowl instantly, 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 means of
Object.getOwnPropertyDescriptor. It may be discovered that there isn’t a writable: true attribute, which implies that
localStorage shouldn’t be instantly writable.
4.2 Overriding with Object.defineProperty
Since there isn’t a
writableattribute, we’ll add one to it. We are able to override
However you may’t use the above writing methodology with one layer exterior. Should you instantly give the above
localStorage then it’s going to generate infinite recursion (to keep away from deceptive, the unsuitable writing methodology won’t be written right here).
I’ve made a backup of
localStorage right here. Should you want a local methodology then you too can function it.
On this article, we don’t particularly implement a operate resembling setting the expiration time. However discuss find out how to rewrite
localStorage or the strategies in it from one other perspective.