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?

useEffect()

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

Conteúdo do Curso

React Tutorial

React Tutorial

useEffect()

useEffect is a hook in React that allows you to perform side effects in function components. It is a way to express side effects in a functional, declarative way, rather than using imperative code.

Here's an example of how to use useEffect:

The function passed to useEffect is called the "effect function". It will be called after the component is rendered. You can think of it as a combination of componentDidMount, componentDidUpdate, and componentWillUnmount in a class-based component.

You can also specify when the effect function should be called by passing a second argument to useEffect. This argument is called the "dependencies array". If you pass an empty array ([]), the effect function will only be called once, after the initial render. If you pass an array of values, the effect function will be called anytime one of those values changes.

In this example, the effect function updates the document title whenever the count value changes. This is useful for updating the UI based on some state.

There are a few nuances to be aware of when using useEffect:

The effect function should be pure, meaning it should not have any side effects other than the ones you explicitly specify.
The effect function should not cause any updates to the component state. If you need to update the state based on an effect, use a useLayoutEffect hook instead.
The effect function will be called every time the component is rendered, not just on the initial render. If you want to perform an effect only on the initial render, you can use the [] dependency array to achieve this.
If you don't specify a dependencies array, the effect function will be called on every render. This can be expensive and may cause performance issues, so it's important to be selective about which values you include in the dependencies array.

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Seção 3. Capítulo 4

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