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There are multiple reasons why the Component cannot be used as a JSX component error appears: Returning an array of JSX elements instead of a single element. Returning any value other than a JSX element or null from a component. Having an outdated ver...

Check if the input value is a valid number in React: Check if the input value is not an empty string or contains only spaces. Pass the value to the isNaN() function. If isNaN returns false , then the value is a valid number. import {useState} from rea...

To detect when the user presses the backspace key in React.js: Add the onKeyDown prop to the input element. Every time the user presses a key in the input field, check if the key pressed was the backspace key. Call a function or run some logic if it i...

To set background color using inline styles in React: Set the style attribute on the element. Set the backgroundColor attribute to a specific color. import {useState} from react ; export default function App () { const [isActive, setIsActive] =...

React.js error X is not defined react/jsx-no-undef occurs when we forget to import a function, class, or variable before using it in our code. To fix this error, make sure to import the value before using it in our code, e.g. import {myFunc} from my-...

To fix the React.js warning Invalid DOM property for . Did you mean tmlFor . Use the htmlFor attribute because for is a reserved word in JavaScript. Here is an example of how the warning is generated. export default function App () { // ⛔️ Warning...

Use the useSearchParams hook to programmatically update query parameters in React Router, for example, setSearchParams({query: myValue}) . The useSearchParams hook is used to read and modify the query string in the URL of the current location. import ...

To set the height of a Div in React to cover the entire screen, set its height to 100vh, for example div style={{height: 100vh}}.../div . When the element's height is set to 100vh, it covers 100% of the viewport height. const App = () = { return...

To focus an input when another element is clicked in React: Set a ref attribute on the input element. Set an onClick attribute on the other element. When the other element is clicked, focus the input, e.g. ref.current.focus() . import { useRef } from ...

When we use a string as a reference in a function component, we get the error Function components cannot have string refs. To fix the error, use the useRef() hook to get a mutable ref object that we can use as a reference inside a component....

To get the value of an input field using ref in React: Set the ref attribute on the input element. Access the value of the input field on the ref object, e.g. ref.current.value . import { useRef } from react ; const App = () = { const inputRef = useRe...

The error React hook useEffect is called conditionally occurs when we use the useEffect hook conditionally or after a condition that may return a value. To fix the error, move all React hooks above any condition that may return a value....

When a component returns multiple elements, you get the React.js error JSX expression must have a parent element. To fix the error, wrap the elements in a parent div element or use fragments, such as h2One/h2h2Two/h2/ . Below is an example that produc...

To type the useState hook in React as an array of strings, use the hook's generics, such as const [names, setNames] = useStatestring[]([]) . State variables can be initialized to an empty array or an array of strings, and only accept string values....

To fix the issue of input fields not working in React, make sure to use the defaultValue property instead of the value of the uncontrolled input field. Alternatively, set an onChange property on the field and handle the change event. Here is an exampl...