React Tutorial

React Tutorial

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1. Getting Started

The prompt provides a list of terms that are commonly used in React, a popular JavaScript library for building user interfaces. The terms include React, component, virtual DOM, JSX, constructor() method, render() method, state, setState() method, props, and binding methods. The prompt does not provide any additional context or information about these terms.

What is a Component?

State and setState()

Props (properties)

Binding Methods

2. Lifecycle Methods

Now that we have become familiar with most of the React basics and how components work and integrate into the development of a website. Since we know that React components are loaded onto the main page and then can be dynamically updated which means that they go through a certain cycle of stages that can be intervened in and the behavior can be updated. This cycle can be manipulated through what are called lifecycle functions at different stages. React class component lifecycle methods are used for a variety of purposes, including performing setup tasks when a component is first rendered, updating a component in response to changes in props or state, and cleaning up any resources that the component is using.

componentWillMount()

componentWillUnmount()

componentDidMount()

shouldComponentUpdate()

componentDidUpdate()

componentDidCatch()

Overview of Component Lifecycle

3. Functional Components and Hooks

Now that we have gone over the basics of class-based components, we will now explore a better and more concise way to write React components with functional components which are a lot more commonly used in React these days. Functional components are a way to define components in React that are simple, lightweight, and only consist of a render function. They are a great choice for simple, presentational components that only need to render some JSX and don't have their own state or lifecycle methods. In this section of the course, we'll look at how to use functional components with Hooks to manage state and other lifecycle events.

What is a Hook?

4. Advanced Topics

Now, we understand the basics of React with regards to the various kinds of components available and how to use them and exploit their lifecycle to our advantage in a webpage, we will now move on to some advanced topics. These topics will deal with topics like state management through Context API and the Consumer and Provider architecture in React and how these things make life easier in a production-level React App. Then we will move onto Routing in react and how it all works to produce a navigable React App without having to reload the page. This involves studying an important React package called “react-router-dom” which we will get into in this section.

React Router Dom

Course Content

React Tutorial

React Tutorial

componentDidUpdate()

componentDidUpdate() is a lifecycle method in React that is called immediately after a component's updates are made to the DOM. It receives two arguments: prevProps and prevState, which are the previous values of the component's props and state, respectively.

Here is a complete example of a React component using the componentDidUpdate lifecycle method:

In this example, the MyComponent component has a state called data, which is an array of items. When the id prop changes, the fetchData function is called to retrieve new data and update the state. The componentDidUpdate method is used to check for changes to the id prop and trigger the data fetch if necessary.

The componentDidUpdate method is called after the component's updates are made to the DOM, so the updated data will be reflected in the rendered output.

Another use case for componentDidUpdate might be to send a network request after a form has been submitted, or to update the title of the document based on the contents of the component.

There are a few important nuances to be aware of when working with the componentDidUpdate method:

componentDidUpdate is called every time the component updates, not just when the props or state changes. This means that if you are using shouldComponentUpdate to optimize performance, you will need to be careful to check for changes to the relevant props or state before performing any updates.
componentDidUpdate is called after the component's updates are made to the DOM, so any DOM manipulation or updates that you perform in this method will trigger a second rendering of the component. This can lead to performance issues if you are not careful.
componentDidUpdate is called after the render method, so the component will already have the updated props and state when this method is called. This means that you cannot use this.props or this.state to get the updated values in this method. Instead, you will need to use the prevProps and prevState arguments.
componentDidUpdate is not called on the initial render of a component. If you need to perform an action after the initial render, you can use the componentDidMount method instead.

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Section 2. Chapter 5

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