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Questions and Answers
According to the 80/20 rule in 'The React Handbook', how much of a topic can you learn in 20% of the time?
According to the 80/20 rule in 'The React Handbook', how much of a topic can you learn in 20% of the time?
80%
Who is the author of 'The React Handbook'?
Who is the author of 'The React Handbook'?
Flavio
What are the primary concepts of React that you need to understand?
What are the primary concepts of React that you need to understand?
What are the core JavaScript concepts that one should have a good overview of before using React?
What are the core JavaScript concepts that one should have a good overview of before using React?
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Why should Web developers have a basic understanding of React?
Why should Web developers have a basic understanding of React?
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_____ is an officially recommended tool for installing React.
_____ is an officially recommended tool for installing React.
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JSX in React is actually HTML code.
JSX in React is actually HTML code.
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What is the name of the attribute used in React JSX that replaces the 'class' attribute in HTML?
What is the name of the attribute used in React JSX that replaces the 'class' attribute in HTML?
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How does JSX handle errors like forgetting to close a tag?
How does JSX handle errors like forgetting to close a tag?
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What is the purpose of the 'useState' hook in React?
What is the purpose of the 'useState' hook in React?
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How can data flow from a child component to a parent component in React?
How can data flow from a child component to a parent component in React?
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Which hook in React allows components to access lifecycle events?
Which hook in React allows components to access lifecycle events?
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What must be included in the array passed as the second parameter to 'useEffect' to ensure it runs only once on mount?
What must be included in the array passed as the second parameter to 'useEffect' to ensure it runs only once on mount?
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React supports various types of DOM events like onClick, onKeyUp, and onChange.
React supports various types of DOM events like onClick, onKeyUp, and onChange.
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Study Notes
The React Handbook
- The React Handbook is a guide to learn React in 20% of the time, focusing on the 80% of the topic.
- The book is written by Flavio, a programming tutorial writer, and bootcamp organizer.
Introduction to React
- React is a JavaScript library that simplifies the development of visual interfaces.
- It was developed at Facebook and released in 2013.
- React aims to make it easy to reason about an interface and its state at any point in time.
- It divides the UI into a collection of components.
What You Need to Know to Use React
- You should have a good understanding of some core JavaScript concepts, such as:
- Variables
- Arrow functions
- Rest and Spread operators
- Object and array destructuring
- Template literals
- Classes
- Callbacks
- ES Modules
Why Learn React?
- React is very popular and widely used in Web development.
- Many tooling and frameworks, such as Next.js and Gatsby, are built on top of React.
- Knowledge of React is a valuable skill for frontend engineers.
How to Install React
- You can install React using the
create-react-app
command line tool. -
npx
is an easy way to download and execute Node.js commands without installing them. -
npx create-react-app
will download the latest version ofcreate-react-app
and create a new React application.
React Components
- A React component is a function that returns JSX.
- A component can have its own state, which means it encapsulates some variables that other components can't access.
- A component can also receive data from other components through props.
Introduction to JSX
- JSX is a special language used to build a component's output.
- JSX looks like HTML, but it's not.
- JSX is processed by React and transformed into JavaScript that the browser can interpret.
Using JSX to Compose UI
- JSX makes it easy to build a UI by importing and embedding other React components.
- A React component can be created in its own file or in the same file as another component.
The Difference Between JSX and HTML
- JSX is not forgiving, unlike HTML, and requires correct syntax.
- In JSX, the
className
attribute is used instead ofclass
due to the reserved wordclass
in JavaScript. - JSX can embed JavaScript expressions using curly brackets
{}
.
Embedding JavaScript in JSX
- JSX allows embedding JavaScript expressions using curly brackets
{}
. - JavaScript expressions can be used to print values, perform conditional statements, and more.
Managing State in React
- Every React component can have its own state.
- The state is the set of data that is managed by the component.
-
useState
is a hook that provides a way to manage state in a React component.
Component Props in React
- Props are the initial values passed to a component.
- Props can be passed as attributes to the component in the JSX.
- Props can be received as an argument in the component function.
Data Flow in a React Application
-
Data typically flows from a parent component to a child component using props.
-
Functions can be passed as props to allow a child component to call a function in the parent component.
-
Changes to the parent component's state can be made from a child component using a function passed as a prop.### Data Management in React
-
There are two common ways to manage data in React: passing props down and using state
-
More advanced ways to manage data include the Context API and libraries like Redux, but these introduce more complexity
Handling User Events in React
- React provides an easy way to manage events fired from DOM events like clicks, form events, and more
- You can use the
onClick
attribute on any JSX element to fire a function when the element is clicked - React supports a vast amount of types of events, including
onKeyUp
,onFocus
,onChange
,onMouseDown
,onSubmit
, and many more
Lifecycle Events in a React Component
- The
useEffect
hook allows components to have access to the lifecycle events of a component - When you call the
useEffect
hook, you pass it a function that will be run by React when the component is first rendered, and on every subsequent re-render/update - The
useEffect
function is run after the DOM is updated, and does not block the UI rendering even on blocking code - You can tell React to skip re-running the side effect by adding a second parameter to
useEffect
, which is an array that contains a list of state variables to watch for - You can also tell React to only execute the side effect once (at mount time) by passing an empty array as the second parameter
Where to Go from Here
- To learn more about React, start by learning more theory about the Virtual DOM, writing declarative code, unidirectional data flow, immutability, and composition
- Build simple React applications, such as a counter or an application that interacts with a public API
- Learn about conditional rendering, loops in JSX, and using the React Developer Tools
- Learn how to apply CSS in a React application, manage state using the Context API,
useContext
, and Redux, and interact with forms - Learn how to use React Router, test React applications, and an application framework built on top of React, like Gatsby or Next.js
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Description
Test your knowledge of React basics, including the 80/20 rule, core concepts, and JavaScript prerequisites. Learn about the importance of React for web developers and tools for installing it.