ReactElement

• A ReactElement is a plain object describing a component instance or DOM node and its desired properties.
• It’s the return type of React.createElement().
• It’s always an object with a type and props.
• It’s more specific and represents a single React element.

const element: React.ReactElement = <div>Hello</div>;

ReactNode

• ReactNode is a more general type that can represent a React element, a string, a number, a boolean, null, undefined, or an array of ReactNodes.
• It’s a union type that includes ReactElement.
• It’s more flexible and can represent any valid value that can be rendered in React.

const node1: React.ReactNode = "Hello";
const node2: React.ReactNode = 42;
const node3: React.ReactNode = <div>World</div>;
const node4: React.ReactNode = [node1, node2, node3];

Key Differences

• Specificity:
  • ReactElement is more specific and always represents a single React element.
  • ReactNode is more general and can represent various types that React can render.
• Usage:
  • ReactElement is typically used when you specifically need a React element.
  • ReactNode is often used for component children or when you want to accept any renderable content.
• Type Hierarchy:
  • ReactNode includes ReactElement, but not vice versa.
  • All ReactElements are ReactNodes, but not all ReactNodes are ReactElements.
• Common Use Cases:
  • ReactElement: When you’re working with specific React components or elements.
  • ReactNode: When defining props that can accept various types of content, like children.

import React, { ReactElement, ReactNode } from 'react';

// This only accepts a single React element
const ElementComponent: React.FC<{ content: ReactElement }> = ({ content }) => {
  return <div>{content}</div>;
};

// This accepts any renderable content
const NodeComponent: React.FC<{ content: ReactNode }> = ({ content }) => {
  return <div>{content}</div>;
};

function App() {
  return (
    <div>
      <ElementComponent content={<span>Hello</span>} /> {/* Valid */}
      {/* <ElementComponent content="Hello" /> */} {/* Invalid */}
      
      <NodeComponent content={<span>World</span>} /> {/* Valid */}
      <NodeComponent content="Hello" /> {/* Also Valid */}
    </div>
  );
}