What is the difference between state and props in React

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In React, both state and props are used to manage and pass data between components, but they serve different purposes.

State:

  • State is a built-in feature of React components that allows them to keep track of and manage their own data.
  • It is mutable and can be changed using the setState() method.
  • State is typically used for data that can change over time, such as user input, form values, or component-specific data.
  • State is defined and managed within the component itself, making it local and accessible only to that component and its child components.

Props:
* Props (short for properties) are used to pass data from a parent component to its child components.
* Props are immutable and cannot be changed within the child component.
* Props are typically used for data that is passed down from a parent component and remains static throughout the component’s lifecycle.
* Props are defined in the parent component and passed down to child components as attributes, allowing them to access and use the data.

Here’s an example in JavaScript and HTML format to illustrate the difference between state and props:

// Parent component
class ParentComponent extends React.Component {
constructor(props) {
super(props);
this.state = {
message: "Hello, World!",
};
}
render() {
return <ChildComponent message={this.state.message} />;
}
}
// Child component
class ChildComponent extends React.Component {
render() {
return <div>{this.props.message}</div>;
}
}
ReactDOM.render(<ParentComponent />, document.getElementById("root"));

In this example, the parent component (ParentComponent) has a state with a message property. This state is passed down to the child component (ChildComponent) as a prop. The child component then renders the message prop within a <div>. As the state changes in the parent component, the updated message prop is automatically passed down to the child component, allowing it to display the latest value.