UsereF () gegen createref ()
The difference is that createRef will always create a new ref.
In a class-based component, you would typically put the ref in an instance property during construction (e.g. this.input = createRef()).
You don't have this option in a function component. useRef takes care of returning the same ref each time as on the initial rendering.
Here's an example app demonstrating the difference in the behavior of these two functions:
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import React, { useRef, createRef, useState } from "react";
import ReactDOM from "react-dom";
function App() {
const [renderIndex, setRenderIndex] = useState(1);
const refFromUseRef = useRef();
const refFromCreateRef = createRef();
if (!refFromUseRef.current) {
refFromUseRef.current = renderIndex;
}
if (!refFromCreateRef.current) {
refFromCreateRef.current = renderIndex;
}
return (
<div className="App">
Current render index: {renderIndex}
<br />
First render index remembered within refFromUseRef.current:
{refFromUseRef.current}
<br />
First render index unsuccessfully remembered within
refFromCreateRef.current:
{refFromCreateRef.current}
<br />
<button onClick={() => setRenderIndex(prev => prev + 1)}>
Cause re-render
</button>
</div>
);
}
const rootElement = document.getElementById("root");
ReactDOM.render(<App />, rootElement);
Jittery Jellyfish