A Comprehensive Guide to Must Know Key React Terminologies For Beginners

Introduction

React has revolutionized the way we build user interfaces for web applications. It's a JavaScript library that makes it easier to create interactive and dynamic UIs. However, diving into React can be intimidating, especially when you encounter a plethora of terminologies. In this article, we will demystify key React terminologies, providing you with a solid foundation for your React journey.

Note: This blog, covers only the surface-level definitions, not in-depth concepts. To know more about the terminologies and their working, please refer to the official react-docs.

Let's begin then 😎

1. Component

A component is a fundamental building block of a React application. It encapsulates the UI and its behaviour into reusable, self-contained modules. Components can be simple, like a button or a form field, or complex, like an entire page.

2. JSX (JavaScript XML)

JSX is a syntax extension for JavaScript. It allows you to write HTML-like code within your JavaScript files. React components are typically written using JSX, making it easier to visualize the structure of your UI.

const element = <h1>Hello, React!</h1>;

3. Props (Properties)

Props are short for properties and are a way to pass data from a parent component to a child component. They are read-only and help make your components dynamic and reusable.

function Greeting(props) {
  return <h1>Hello, {props.name}</h1>;
}

<Greeting name="Vaheed" />

4. State

The state represents the internal data of a component. Unlike props, state can be modified by the component itself. When state changes, React re-renders the component to reflect the new data.

import React, { useState } from 'react';

function Counter() {
  const [count, setCount] = useState(0);

  return <p>Count: {count}</p>;
}

5. Component Lifecycle

React components go through a series of phases known as the component lifecycle. Key methods like componentDidMount, componentDidUpdate, and componentWillUnmount allows you to hook into these phases and perform actions at specific points during a component's life.

6. Functional Components

Functional components are a simpler way to define React components using functions instead of classes. With the introduction of React Hooks, functional components can now also manage state and lifecycle effects.

function FunctionalComponent(props) {
  return <p>Hello, {props.name}</p>;
}

7. React Hooks

Hooks are functions that let you "hook into" React state and lifecycle features from functional components. The most common hooks include useState, useEffect, and useContext.

import React, { useState, useEffect } from 'react';

function Example() {
  const [count, setCount] = useState(0);

  useEffect(() => {
    document.title = `Count: ${count}`;
  }, [count]);

  return (
    <div>
      <p>Count: {count}</p>
      <button onClick={() => setCount(count + 1)}>Increment</button>
    </div>
  );
}

8. Virtual DOM

React uses a Virtual DOM (a lightweight in-memory representation of the real DOM) to optimize rendering performance. When state or props change, React compares the Virtual DOM with the actual DOM and updates only the parts that have changed, minimizing expensive DOM operations.

9. Reconciliation

Reconciliation is a crucial process within React's rendering algorithm. It's responsible for updating the actual DOM to match the desired UI representation based on changes in component state or props. React's goal is to be highly efficient, and reconciliation plays a significant role in achieving this efficiency.

10. React Fragments

React Fragments are a way to group multiple children without adding extra nodes to the DOM. They allow you to avoid unnecessary container elements when you want to return multiple elements from a component.

function FragmentExample() {
  return (
    <>
      <p>First paragraph</p>
      <p>Second paragraph</p>
    </>
  );
}

11. Higher-Order Components (HOCs)

Higher-order components are functions that take a component and return a new enhanced component. They are used for code reuse, logic extraction, and adding additional props or behaviour to a component.

import React, { useEffect } from 'react';

function withLogger(WrappedComponent) {
  return function EnhancedComponent(props) {
    useEffect(() => {
      console.log('Component is mounted.');
    }, []);

    return <WrappedComponent {...props} />;
  };
}

const EnhancedComponent = withLogger(MyComponent);

In this example, withLogger is a higher-order component that adds a logging behaviour to MyComponent.

12. React Portals

React Portals provide a way to render a component's children into a different part of the DOM hierarchy, typically outside the parent component's DOM tree. This is useful for scenarios like creating modal dialogues or tooltips.

import ReactDOM from 'react-dom';

function Modal(props) {
  return ReactDOM.createPortal(
    props.children,
    document.getElementById('modal-root')
  );
}

function App() {
  return (
    <div>
      <p>Content in the main app</p>
      <Modal>
        <p>Modal content</p>
      </Modal>
    </div>
  );
}

Conclusion

React is a powerful and flexible library for building modern web applications. As you navigate the world of React development, understanding these key terminologies is essential. Whether you're working with components, managing state, optimizing performance through reconciliation, or exploring advanced concepts like Higher-Order Components and Portals, these terms will be your building blocks for creating robust and efficient React applications.

Remember that React is a dynamic ecosystem with ongoing advancements and best practices. Continuously learning and mastering these terminologies will empower you to create engaging and interactive user interfaces while keeping your codebase maintainable and performant. Happy coding!

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