[4] React Native App File Structures | Understand React Native File Structure| React Native Tutorial

Summary

In this React Native course video, the instructor provides an overview of the file structure crucial for beginners. Key topics covered include the significance of important files like package.json, Metro config, index.js, and app.jsx. The instructor explains how these files track dependencies, handle configuration, and ensure smooth app development. Additionally, testing files and ESLint rules are discussed, along with the role of iOS and Android folders in project building. The video also touches on interview questions related to these files, with more fundamental topics promised in future sessions.

Takeaways

• 📁 React Native file structure overview including key files for beginners.
• 📦 Importance of `package.json` file in managing dependencies and scripts for the project.
• 🛠️ Discussion on Metro config file, enabling instant reflection of code changes.
• 📄 Explanation of `index.js` as the root file responsible for registering app components.
• 📝 Difference between `.jsx` and `.js` files, with `.jsx` offering HTML-like suggestions for code.
• ⚙️ Role of Babel in converting ES6+ code to browser-compatible versions for React Native apps.
• 🚫 Explanation of `.gitignore`, preventing certain files (like `node_modules`) from being pushed to GitHub.
• 💻 ESLint helps ensure code quality by enforcing coding rules and style guidelines.
• 📂 iOS and Android folders hold platform-specific code and may need adjustments when working on apps.
• ✅ Prettier is used to auto-format and clean up code for consistency across the project.

Q & A

What is the primary purpose of the package.json file in a React Native project?

The package.json file keeps track of every dependency used in the project, including the project's name, version, and scripts. It is one of the most important files for an app.

What is the difference between JSX and JS in the context of React Native?

JSX stands for JavaScript XML and allows you to write HTML-like code within JavaScript. It provides suggestions and is used instead of plain JS for React Native to enable the writing of UI components.

Why is the Metro config file important in React Native?

The Metro config file is crucial for enabling rapid updates and reflecting changes made in the code immediately in the app.

What is the role of the .babelrc file in a React Native project?

The .babelrc file is used for configuring Babel, a transpiler that converts ES6 code into browser-compatible code, ensuring compatibility across different systems and browsers.

What does the index.js file do in a React Native project?

The index.js file is the root file where the main app component is registered. It imports and renders the App component.

What is the purpose of the .gitignore file in a React Native project?

The .gitignore file specifies intentionally untracked files that Git should ignore, such as node_modules or build files, preventing them from being pushed to GitHub.

What is the function of the .prettierrc file in code development?

The .prettierrc file is used to define rules for code formatting. It helps to maintain consistency and readability in the codebase.

Why is the node_modules folder not pushed to GitHub in a React Native project?

The node_modules folder is not pushed to GitHub because it contains dependencies that can be reinstalled using npm or yarn, and it can be quite large, reducing the repository size and improving performance.

What is the significance of the iOS and Android folders in a React Native project?

The iOS and Android folders contain platform-specific code and configurations necessary for building and running the app on their respective platforms.

How does the Watchman config file contribute to a React Native project?

The Watchman config file is responsible for monitoring file changes and notifying Metro about these changes, which then reflects them in the app.

What are the ESLint rules and where are they defined in a React Native project?

ESLint rules are defined in the .eslintrc file and are used to enforce style and conventions in the JavaScript code, ensuring code quality and consistency.

Outlines

00:00

📂 Introduction to React Native File Structure

In this video, the presenter introduces the React Native course and specifically focuses on explaining the file structure. The discussion covers important files and folders necessary for beginners, such as `package.json`, `Metro config file`, `index.js`, and `app.jsx`. The video also touches on key differences between JavaScript (JS) and JavaScript XML (JSX), where JSX allows writing HTML-like code that provides suggestions during development. A previously created project is opened using the `npx react-native` command. The importance of `package.json` is emphasized, as it keeps track of dependencies for both the app and its development, while `package-lock.json` handles sub-dependencies. The presenter also explains why JSX is used instead of JS.

05:01

🛠️ Detailed Breakdown of Files in React Native

This section continues the deep dive into the React Native file structure, discussing the functionality of different files and their uses. The `Watchman` config file monitors changes to files and triggers updates, while `prettier` helps format and maintain code quality. The `.gitignore` file prevents certain files, like `node_modules`, from being pushed to GitHub. Additionally, ESLint enforces coding rules for better formatting. The section also explains the role of the iOS and Android folders in making app-specific changes and the purpose of test files for writing test cases. Finally, the session concludes by introducing the fundamental components of React Native, such as `View`, `Text`, and `Button`, which will be covered in the next video.

Keywords

💡React Native

React Native is a popular framework developed by Facebook for building mobile applications using JavaScript and React. It allows developers to build native apps for iOS and Android using a single codebase. In the video, the instructor discusses the file structure of a React Native project, which is essential for understanding how to navigate and manage the project files.

💡package.json

The package.json file is a crucial component of any Node.js project, including React Native apps. It contains important information about the project, such as its name, version, dependencies, and scripts for running tasks. In the video, the instructor emphasizes the importance of this file for tracking all the dependencies used in the app.

💡Metro Config

Metro is the JavaScript bundler used by React Native for bundling assets and transforming JavaScript code. The Metro config file is used to configure the behavior of the Metro bundler, such as specifying the project root, providing module paths, and configuring platform-specific settings. The instructor mentions that changes in the project are reflected in the app due to Metro Config.

💡index.js

The index.js file is typically the entry point for a React Native application. It is where the main app component is registered and rendered. The script mentions that this file is essential as it sets up the initial rendering of the app components.

💡ESLint

ESLint is a static code analysis tool used to enforce code quality and consistency in JavaScript projects. It helps identify and fix problems in the code, such as syntax errors or style issues. In the video, the instructor discusses how ESLint is used during development to ensure code quality but is not used in production.

💡Babel

Babel is a JavaScript compiler that allows developers to use the latest JavaScript features in their code, even if the current environment does not support them. It transforms modern JavaScript code into a version that can be executed by older browsers and environments. The video mentions Babel as a tool that converts ES6 code into browser-compatible code.

💡App.jsx

App.jsx is the main component file in a React Native project. It serves as the root component that contains the rest of the app's components and defines the app's initial UI. The instructor explains that App.jsx is used instead of App.js because JSX allows writing HTML-like code within JavaScript, which provides better suggestions and readability.

💡Watchman

Watchman is a file-watching service developed by Facebook that watches files and records when they change. It is used by React Native to watch for changes in the project files and trigger a rebuild when necessary. The video script mentions Watchman Config as a way to configure Watchman's behavior.

💡Prettier

Prettier is an opinionated code formatter that supports many languages, including JavaScript. It enforces a consistent style by parsing the code and reprinting it with its own rules that take the maximum line length into account, wrapping code when necessary. The instructor talks about Prettier in the context of maintaining code quality and consistency.

💡.gitignore

A .gitignore file is used to tell Git which files or folders to ignore in source control. This is useful for excluding build artifacts, node_modules, or other files that shouldn't be tracked by Git. The video script refers to .gitignore when discussing which files should not be pushed to GitHub.

💡iOS and Android folders

In a React Native project, the iOS and Android folders contain platform-specific code and resources for the respective platforms. These folders allow developers to write native code when necessary and manage platform-specific assets. The instructor mentions these folders in the context of making changes to the app for different platforms.

Highlights

Introduction to React Native file structure, focusing on key files and folders important for beginners.

Explanation of the 'package.json' file, its role in tracking dependencies, and its critical importance for the app.

Discussion on the difference between 'jsx' and 'js' and why 'jsx' is used in React Native projects.

Introduction to the 'Metro config' file, which enables instant reflection of code changes in the app.

Overview of 'just config' file for setting up test cases in the app.

Description of 'index.js' as the root file where the app component is registered.

Brief explanation of 'babel config' for converting ES6+ code into browser-compatible formats.

Overview of 'Watchman config,' which monitors file changes and ensures updates are reflected in the app.

Explanation of the role of 'prettierrc' in enforcing code formatting and best practices.

Discussion on the use of '.gitignore' file to prevent pushing unnecessary files like 'node_modules' to GitHub.

Introduction to 'ESLint rules' for maintaining clean, consistent JavaScript code and the possibility of extending them.

Explanation of 'node_modules,' the folder where all installed dependencies are stored.

Overview of the 'iOS' folder and its role in making changes for the iOS platform when required.

Discussion on the 'Android' folder and how it manages platform-specific adjustments and bundling.

Preview of the next session, where the fundamentals of React Native, such as views, text, and buttons, will be discussed.

Transcripts

so hey guys welcome back to the react

native course in this video we are going

to talk about the react native file

structure okay so let's see so first we

are going to talk about the important

file for beginners we will explain the

files and folder and we will also

discuss the interview questions okay the

important files that you should know the

first important file is called

package.json so you should know like

what is package.json file we also talk

about the what is Metro config file what

is Apple config file what does index. DS

do what is the use of app.jsx and we

also talk about the what is ESL RC and

we will also talk about the IOS and

Android folder so let's jump on the BS

code so you can see that I've already

created one project in the last video

using the npx react native at theate

latest in IT project name okay so in the

last video we have seen that uh we have

done some some changes from app.jsx like

it was initially app. TSX it was like

using TS uh but we changed into the JS

okay jsx what is the difference between

jsx and JS so jsx is stand for

JavaScript XML so where we can write the

HTML like looking code so it will give

you suggestion and that's why we use App

jsx instead of using the

JS okay so let's talk about the some

file of let's talk about the first

package.json so what is package.json

file so package.json is something which

file which keep track of every

dependency whatever you guys use and

package. Jon is one of the most popular

file one of the most important file for

your app okay so say there you can see

the name of the package in it and the

version and the script file script file

has some you know script like that is

that uh script has some certain task so

whenever you run a command npm running

start it will hit this command and when

you run the npm in Android so it will

start this command okay so if you talk

about the dependency so our react

project the reative B plate is using two

dependency the first dependency is react

and the second one is called react

native okay now there are some de

dependency what is De dependency

basically which are helping this project

in the development as d stand for

development so there is our dependency

they are helping them to develop our app

and the development so in the

development we are using Babble code

Babble learn time and so on eslint and

eslint has no use in the uh you know

production this there uh dependency are

just using in the development and we are

using the node more than 18 version you

can see the TS config we are not using T

TS config so if you want to do any

configuration for typ script you can add

it here rm. MD file here you can add any

rmy like whatever you want to tell about

like how to set up your project and so

on now what is package Lo Jon so

basically uh every you know like react

is a package okay so it has some uh it

has some some sub dependency so package

log J will keep track of that dependency

as well

as as well as the sub

dependency okay and that's why like you

know package loog J is there but one of

the if you delete the package L J it

doesn't affect anyway but you should uh

if you lost the package.json it means

you lost your project so package.json is

one of the most important file and you

have to take care of that let's talk

about the what is Metro config file so

whenever we do some changes okay and it

will reflect in our app let's suppose if

I do some changes uh okay so it will

suddenly reflect that changes after

saving that okay and this is Possible

only by the metro config okay now just

config is for the testing purpose so if

you want to write some test cases for

your app so you have to use just config

file we have index.js so basically it is

a root file where we registered the our

app component so we are just importing

the app component and we are registering

this component

okay Zim file has some you know it has

used for Ruby gyms okay and we don't

have to think about right now we we are

not going to use anymore and what is

bble config so basically what do happen

now we write T is a trans compiler which

convert es6 code into the browser

understandable a browser compatibility

code okay so basically let's suppose we

write the es7 es6 code but our react

native or our system or our browser

doesn't understand that es7 is s it so

it will convert to the compatible form

that browser or apps can understand okay

app.jsx we talk about this already what

is app.js file here we can you know

write the that name and display name

Watchman config okay as the name suggest

Watchman so it will watch our file so

this is the Watchman has a job to you

know keep the watch of the every file

and whatever the changes it will do it

will tell you the metro and Metro will

you know deflect that changes quickly

what is prier rcfl so basically prier is

a PR it will pred defy our code let's

suppose if I you know hit some you know

uh if I make the code very wrong like

you know it's not a good manner so P

will help P will throw error man uh you

are not

using uh back you are not using writing

space you are not using quotes you are

not using uh you know that will throw

err like you know to make your code

prettier and that's is the use of PR G

ignore G ignore file is something which

you know which we G ignore file has a

use that let's suppose if you don't want

to push some file certain files on the

GitHub and so while pushing the code it

will ignore that file that's the job of

of G let's suppose we don't want to push

node modul so we have node modulus in

the G ignore same for theb file we don't

P we don't put on the on the uh GitHub

so yeah we let's talk about the es L

rules so whatever we write the

JavaScript so to make it Prett we Define

a certain rule so that was defined that

rules are defined in the US link and we

can want to extend some rules more like

like you allow for Arrow fun and some

more so you can add this all what is the

use of not model so whenever we install

the package like you know uh whenever we

do npmi we install the node mod whenever

we install the Independence that went to

the node

modulos what is the use of iOS so let's

suppose we are using some we are using

some changes so sometimes we have to do

some changes inside our app and that's

why it is a use of iOS folder Android

folder has also some use case so let's

suppose we we build our app or we

install some dependency so we have to do

some changes on the invite folder and

whenever we bundle our app so that will

reflect on the bundle folder and the

test file has used whenever we write app

to test cases for our app okay so this

is the file structure of our react

narative in the next session we will

talk about the fundamental of react

narative like how to uh what is view

what is text what is button and so on so

yeah thanks we will catch up in the next

video and let me know if you guys have

any question or any doubt

thanks