WebJun 12, 2024 · If the useRef is initialized with null and the initial value does not belong to the provided type, the current property is immutable. In our case, the null initial value does not belong to the type HTMLInputElement so the current property cannot be mutated. Mutable current property WebJul 15, 2024 · The code below illustrates how to invoke the useRef hook in functional components. const myRef = React.useRef(null); // You can use a descriptive variable name instead of myRef. myRef, which is returned by a call to useRef hook is an object which looks like {current: null}.
How To Use React useRef Hook (with Examples) - Upmostly
WebApr 10, 2024 · The ref's current property will be null until/unless it's set. In your case, you're using it in a useEffect callback, so assuming you've used the ref on an element that was rendered, it won't be null when you try to use it. But TypeScript doesn't know that, so it warns you of this possible error. WebA React ref most commonly returns undefined or null when we try to access its current property before its corresponding DOM element is rendered. To get around this, access the ref in the useEffect hook or when an event is triggered. I wrote a book in which I share everything I know about how to become a better, more efficient programmer. how much light is reflected
What is the purpose of the useref hook in react? - Rjwala
WebFor some reason, in this line onChange= { (event: ChangeEvent) => setImage (event.target.files [0])}, event.target.files [0] gives the error Object is possibly 'null' When I change the line to: onChange= { (event: ChangeEvent) => { if (!event.target.files) return setImage (event.target.files [0]) }} WebApr 6, 2024 · This makes the ternary operator in render null — and not render the div element. Thus elementRef in the parent becomes null. 5.2 Pass ref using a prop. In the … WebUse this package to find the types, then set the type for useRef and initialise it with null. const mapRef: Type = React.useRef (null); // Replace `Type` with the actual type from the … how do i know what kind of hp laptop i have