React Props: How to Pass Data Between Components

In React, props are a way to pass data from a parent component to its child components. This allows you to share data and information throughout your application. In this blog post, I will explain how to use props in both function and class components.

Using Props in Function Components

In a function component, props are passed as an argument to the function. You can access the props by adding props as the function argument. Here’s an example:

const BlogPostExcerpt = (props) => {
  return (
    <div>
      <h1>{props.title}</h1>
      <p>{props.description}</p>
    </div>
  );
};

Using Props in Class Components

In class components, props are passed by default. There is no need to add anything special. You can access the props using this.props in a Component instance. Here’s an example:

import React, { Component } from 'react';

class BlogPostExcerpt extends Component {
  render() {
    return (
      <div>
        <h1>{this.props.title}</h1>
        <p>{this.props.description}</p>
      </div>
    );
  }
}

Passing Props to Child Components

Passing props down to child components is a great way to share values and data throughout your application. You can either hold data in a component’s state or pass it through props. This allows child components to receive and utilize the data from their parent component.

Handling Default Values for Props

If a prop value is not required, you can specify a default value for it when the Component is initialized. This is useful when you want to ensure that a prop has a value even if it’s not explicitly passed. Here’s an example:

BlogPostExcerpt.propTypes = {
  title: PropTypes.string,
  description: PropTypes.string
};

BlogPostExcerpt.defaultProps = {
  title: '',
  description: ''
};

Tools like ESLint can enforce defining defaultProps for components with propTypes that are not explicitly required.

Passing Props to Components

When initializing a component, you can pass the props in a similar way to HTML attributes. Here’s an example:

const desc = 'A description';

<BlogPostExcerpt title="A blog post" description={desc} />

In this example, we passed the title as a plain string and the description as a variable.

Using the `children` Prop

A special prop in React is children, which contains the value of anything that is passed in the body of the component. This allows you to include dynamic content within your components. Here’s an example:

<BlogPostExcerpt title="A blog post" description="{desc}">
  Something
</BlogPostExcerpt>

In this case, inside the BlogPostExcerpt component, you can access the value “Something” by looking up this.props.children.

Props are a powerful feature in React that enable you to pass data between components in a straightforward and efficient way. By understanding how to use props effectively, you can create dynamic and interactive applications.

Using Props in Function Components#

Using Props in Class Components#

Passing Props to Child Components#

Handling Default Values for Props#

Passing Props to Components#

Using the children Prop#