What is the difference between a Presentational and Container component?

Vaibhav Kothia May 26, 2023 0 Comments

Presentational components are concerned with how things look. They usually receive data and callbacks exclusively via props. These components are usually written as functional components unless they need to use state or lifecycle methods.

Example:

const Button = (props) => {
return {props.text}
}

Container components are concerned with how things work. They are often stateful, as they tend to serve as data sources. These components are usually written as class components.

Example:

class ButtonContainer extends React.Component {
constructor(props) {
super(props);
this.state = {
text: ‘Click Me!’
}
}

handleClick = () => {
this.setState({
text: ‘You clicked!’
});
}

render() {
return
}
}

How does React handle user input?

Vaibhav Kothia May 26, 2023 0 Comments

React handles user input by using the onChange event handler. This event handler allows the user to input data, which is then stored and can be used to update the state of the application.

For example, if you had a form with an input field, you could use the onChange event handler to update the state of the application with the user’s input.

In the example below, we have a form with an input field and a button. When the user types something into the input field and clicks the button, the onChange event handler is triggered and the value of the input is stored in the state of the application.

function App() {
const [inputValue, setInputValue] = useState(”);

const handleChange = (e) => {
setInputValue(e.target.value);
}

return (

Submit

);
}

export default App;

What are the different ways of creating components in React?

Vaibhav Kothia May 26, 2023 0 Comments

1. Function Components: Function components are the simplest way to define a component in React. It is a JavaScript function that accepts props as an argument and returns a React element.

Example:

const MyComponent = (props) => {
return (

);
};

2. Class Components: Class components are JavaScript classes that extend the base React Component class. They provide more features and capabilities than function components, such as state and lifecycle methods.

Example:

class MyComponent extends React.Component {
render() {
return (

);
}
}

3. Pure Components: Pure components are components that extend the base React.PureComponent class. They are similar to class components in that they can have state and lifecycle methods, but they are optimized for performance by implementing shouldComponentUpdate() with a shallow prop and state comparison.

Example:

class MyComponent extends React.PureComponent {
render() {
return (

);
}
}

4. Stateless Functional Components: Stateless functional components are similar to function components in that they are JavaScript functions that accept props as an argument and return a React element. The difference is that they do not have state or lifecycle methods.

Example:

const MyComponent = (props) => {
return (

);
};

What are the advantages of using React?

Vaibhav Kothia May 26, 2023 0 Comments

1. Easy to Learn: React is a very easy-to-learn library and its syntax is similar to HTML, making it easier for developers to pick up.

2. Reusable Components: React allows developers to create reusable components, which can be used again and again in different projects. For example, a search bar component can be used in multiple projects, saving developers time and effort.

3. Performance: React uses a virtual DOM which helps to make applications more performant. Instead of reloading the entire page when changes are made, React only updates the parts of the page that need to be changed, resulting in faster page loads.

4. Scalability: React is designed to scale up, making it ideal for large-scale applications.

5. Flexibility: React is highly flexible and can be used to build mobile applications as well as web applications.

What is the virtual DOM and how does it work?

Vaibhav Kothia May 26, 2023 0 Comments

The virtual DOM (VDOM) is a programming concept where an ideal, or “virtual”, representation of a UI is kept in memory and synced with the “real” DOM by a library such as ReactDOM. The virtual DOM is a lightweight JavaScript object which originally is just the copy of the real DOM. It is a node tree that lists the elements, their attributes and content as Objects and their properties.

Whenever a change is made, the virtual DOM will update instead of the real DOM. This allows for faster updates and better performance. When the virtual DOM has been updated, a diff algorithm will identify what has changed in the virtual DOM. Then, the real DOM will be updated with only the things that have changed.

For example, if you have a button in your application that changes the background color of a page when clicked, the virtual DOM will first determine what has changed. In this case, it will recognize that the background color has changed. Next, the diff algorithm will identify the difference between the virtual DOM and the real DOM and update the real DOM with the new background color.

What is the purpose of using React?

Vaibhav Kothia May 26, 2023 0 Comments

React is a JavaScript library used for building user interfaces. It is a declarative, efficient, and flexible JavaScript library for building user interfaces. It is used for creating single-page applications and mobile applications, as well as for creating complex user interfaces.

For example, when building a web page, React can be used to create components that can be reused throughout the page. React components can be used to create interactive elements such as buttons, menus, and forms. React also allows developers to create reusable components that can be used across multiple web pages. This makes it easier to maintain and update code, as well as reducing development time.

What are the major features of React?

Vaibhav Kothia May 26, 2023 0 Comments

1. Components: React components are the building blocks of any React application. They are pieces of code that can be reused throughout your application. For example, a Button component might be used to render a button in multiple places throughout your application.

2. Virtual DOM: The Virtual DOM is a JavaScript representation of the actual DOM. It is a lightweight and fast way of updating the view when the state changes.

3. JSX: JSX is a syntax extension to JavaScript that allows you to write HTML-like code in your React components. It makes it easier to read and write React components.

4. Props: Props are used to pass data from one component to another. They are like function arguments that are passed in when a component is rendered.

5. State: State is used to store data that changes over time. It is an object that is managed within a component and can be accessed and updated using setState.

6. Lifecycle Methods: Lifecycle methods are methods that get called at certain points in a component’s life. They allow you to perform certain actions when a component is created, updated, or destroyed.