When to use JSX.Element vs ReactNode vs ReactElement?

In React, JSX.Element,ReactNode, and ReactElement are types used to represent different aspects of React components and JSX elements.

JSX.Element

JSX.Element represents the result of compiling JSX code.

We would use JSX.Element when you want to specify the return type of a function component that returns JSX.

Example:

import React from 'react';

function MyComponent(): JSX.Element {
  return <div>Hello, world!</div>;
}

ReactNode

Definition: ReactNode represents a renderable child in React. It can be a React element, string, number, array, fragment, or boolean.

We would use ReactNode when you want to accept any renderable content as children in your component, regardless of its type.

Example:

import React, { ReactNode } from 'react';

interface Props {
  children: ReactNode;
}

function MyComponent({ children }: Props) {
  return <div>{children}</div>;
}

ReactElement

ReactElement represents a React element, which is a lightweight description of what to render.

We would use ReactElement when you need to check if a variable is a React element specifically.

Example:

import React, { ReactElement } from 'react';

function isElement(element: any): element is ReactElement {
  return React.isValidElement(element);
}


const element = <div>Hello, world!</div>;
if (isElement(element)) {
  console.log('This is a React element.');
}

Summary

Use JSX.Element to specify the return type of a function component.

Use ReactNode to accept any renderable content as children in your components.

Use ReactElement when you need to check if a variable is a React element specifically.

In practice, you’ll often find yourself using JSX.Element to specify return types and ReactNode to handle children in your components.

ReactElement is less commonly used directly in application code but can be useful in certain utility functions or type guards.