A StrictMode safe hook that will create disposable instance during render
npm install use-disposableA hook that creates disposable instances during render phase that works with strict mode.
With the introduction of stricter strict mode in React 18, factories
in hooks like useMemo and useState are called twice but useEffect still disposes once. The component will be mounted and unmounted. This makes
it hard to create instances during render time that would be cleaned up by useEffect. Let's look at an example
where we try to create a Portal component.
``tsx
import * as React from "react";
import * as ReactDOM from "react-dom";
function Portal({ children }) {
const domNode = React.useMemo(() => {
const newElement = document.createElement("div");
document.body.appendChild(newElement);
console.log("create DOM node");
return newElement;
}, []);
React.useEffect(() => {
console.log("effect");
return () => {
console.log("dispose DOM node");
domNode.remove();
};
}, [domNode]);
console.log("render to portal");
return ReactDOM.createPortal(children, domNode);
}
`
Let's look at the console output:
`
> create DOM node
> render to portal
> create DOM node
> render to portal
> effect
> dispose DOM node
> effect
The result: Nothing is in the portal šØšØ why?
During the first render to portal the changes are not commited to DOM and in the end there is one empty
portal DOM node. Only after the second render are the DOM changes commited and our content rendered to the
second portal DOM node. However this triggers a simulated mount/unmount and our portal DOM
node is disposed š
`tsx
import * as React from "react";
import * as ReactDOM from "react-dom";
import { useDisposable } from "use-disposable";
function Portal({ children }) {
const domNode = React.useDisposable(() => {
const newElement = document.createElement("div");
document.body.appendChild(newElement);
console.log("create DOM node");
return [newElement, () => newElement.remove()];
}, []);
console.log("render to portal");
return ReactDOM.createPortal(children, domNode);
}
`
The resulting console output:
`
> create DOM node
> render to portal
> render to portal
useDispose makes sure that even in strict mode that in both renders only one instance DOM node is created and used.
This is a hook that uses the React fiber to detect if the StrictMode component is in the tree. It powers useDisposable and
is also available from this package as a standalong utility.
ā ļø Calling useDispose` twice in the same component will lead to unpredictable results, make sure this is only called once
per component, we are actively trying to find ways around this limitation.
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