迹忆客 EN >

Generates the error Functions are not valid as a React child. This may happen if you return a Component instead of from render. There are 2 common reasons: Returning a function reference instead of a component from render. Using React Router routes as...

Use spread syntax to combine multiple inline style objects in React, for example style={{...style1, ...style2}} . The spread syntax will unpack the key-value pairs of the object into a final object and the styles will be applied to the element. export...

To cross out text on click in React: Set an onClick attribute on the element. When the element is clicked, check if its text-decoration attribute is set. If the attribute is set, remove it, otherwise set it to line-through. const App =...

To open a file input on button click in React: Set the onClick attribute on the button element. Set the ref attribute on the file input. When the button is clicked, open the file input, e.g. inputRef.current.click() . App.js import { useRef } from...

To go back to the previous page with React Router: Use the useNavigate() hook, e.g. const navigate = useNavigate(); . Calls the navigate() function passed to it -1 - navigate(-1) . Calling navigate with -1 is the same as clicking the back button. impo...

Use the textDecoration property to add a strikethrough to text in React, for example, span style={{textDecoration: line-through}} . The text-decoration CSS property sets the appearance of text decoration lines. const App = () = { return ( div h2 span ...

To qualify the useState hook object in React, use the hook's generic type, for example, const [employee, setEmployee] = useState{name: string; salary: number}({name: ,salary: 0}) . The state variable will only accept key-value pairs of the specified t...

Adding types to the useRef hook might be a little confusing at first, let’s look at why that is: import {useEffect, useRef} from react ; export function RefDemo () { const inputRef = useRef (); useEffect ( () = { inputRef. current . fo...

To concatenate JSX elements into an array in React: Initialize an empty array. Use the push() method to push JSX elements into the array. Set the key attribute on the outermost JSX element to a unique value. export default function App () { const fru...

React.jsAttempted import error X is not exported from appears when we try to import a named import that does not exist in the specified file. To resolve the error, make sure the module has named exports and that we are not mixing named exports with de...

To create N identical components/elements in React: Use Array.from() method to generate an array of N elements. Replace each element in the array with the actual component. Render the array of elements. function Header () { return h2 Hello world / h2 ...

The Nothing was returned from render React error occurs when we forget to explicitly return a value from a function or class component. To fix the error, explicitly return JSX from our component, use implicit returns with arrow functions, or...

To prevent a page refresh when a form is submitted in React, use the preventDefault() method on the event object, for example event.preventDefault() . The preventDefault() method prevents the browser from taking the default action, which in the case o...

When we use the useState hook to declare an empty state array but do not type the array, we get the error Type is not assignable to type never. To fix the error, use generics to type the state array, such as const [arr, setArr] = useStatestr...

Unexpected default export of anonymous function warning is caused when we try to export an anonymous function using default export. To fix the error, name the function before exporting it. Below is a sample code Header.js that produces the above error...