React Native allows developers to build native mobile apps using React and JavaScript. It uses the same fundamental design as React, using declarative code and components to build user interfaces. The JavaScript code runs on a separate thread, while native modules handle platform-specific tasks on each device. A bridge facilitates communication between the JS thread and native modules, allowing interfaces built with React to render natively on iOS and Android.

1. INTRO TO REACT NATIVE

2. WHAT IS REACT ?
React is a declarative, efficient, and flexible JavaScript library for
building user interfaces. It lets you compose complex UIs from small
and isolated pieces of code called “components”.

3. WHAT IS REACT NATIVE ?
React Native is a framework developed by Facebook for creating
native-style apps for iOS & Android under one common language,
JavaScript .React Native lets you build mobile apps using only
JavaScript. It uses the same design as React

4. HOW DOES REACTJS AND REACT
NATIVE WORK ?

5. REACT NATIVE ARCHITECTURE

6. TERM’S DESCRIPTION
• Main Thread:- This is the main thread which gets spawned as soon as the application
launches. It loads the app and starts the JS thread to execute the Javascript code.
• Shadow Thread :- Once the Javascript loads, the JS thread sends the information on
what needs to be rendered onto the screen. This information is used by a shadow node
thread to compute the layouts
• JS Thread :- The Javascript Queue is the thread queue where main bundled JS thread
runs. The JS thread runs all the business logic, i.e., the code we write in React Native.
• Native Modules :- Apart from the threads spawned by React Native, we can also
spawn threads on the custom native modules we build to speed up the performance
of the application

7. THE BRIDGE
In React Native, the bridge endorses the message broker role, handling
asynchronous commands between the two different worlds. The bridge
is built in C/C++ and thus, can be run on multiple platforms

8. THE NATIVE SIDE
• Let’s begin with the iOS platform. Since Obj-C is an extension of the C
language, it can communicate with it natively.
• On Android, we need to rely on the Java Native Interface to dialog
with the bridge.

9. WHAT HAPPEAN TO
OUR JAVASCRIPT
CODE ?
The UI is compiled by the
component exposed by the
React Native. But, the logic
which is written in Javascript
is going to stay Javascript
.React Native create a
Javascript environment can
run

10. HOW REACT NATIVE PROJECT
START

11. PROBLEMS WITH REACT
NATIVE
No or very little Cross-
Platform Styling of
Components
Only a Basic Set of
Pre-Built Components
Tools to create
Responsive Designs
but no
Responsiveness out
of the Box