With React Native, the most important thing is to understand the ecosystem and how it comes together to create an app. By understanding the overall architecture, we will be able to take the full of advantage the platform.

The course will start by covering the fundamentals like setting up the navigation, setting up the screens, styles, and the UI elements, before moving on to more advanced topics such as state management, crash/error reporting, setting up analytics and middlewares, debugging, and performance optimizations. We will also learn how to avoid/fix frame drops - possibly the most watched parameter of any UI application.

We will also build a Design System and will follow the [Atomic Design Pattern](https://atomicdesign.bradfrost.com/chapter-2/) of building layouts. A Design System primarily consists of three parts:
- UI Inventory and Patterns
- Typography
- Spacing and Styles

We will cover these in detail through the modules of the course. We will also learn about the React Native best practices, how to avoid rabbit holes, and focus on building a performant app.

**This is an opinionated way of building apps with React Native**. The fundamentals discussed in the course, like Atomic Design Pattern and Design System, can be applied to building any UI application, not just ones using React Native.

## One Complete App

The course comes with one complete eCommerce sample app that is discussed through the modules of the course.

## Up-to-date

The course builds on an open-source boilerplate template and is kept up to date with React, React Native and dependent library versions. It is also updated with the latest APIs and libraries that are introduced, like Hooks, hermes, flipper etc.

## Why this course

React Native for JavaScript Developers using TypeScript is based on years of experience in building React Native apps on production. The open-source boilerplate code discussed in the course is the platform for multiple apps on App Store and Play Store today. One of them being a Unicorn.

We will take a **Product** based development approach to building apps. React Native abstracts out a lot of platform specific nuances, so wouldn't focusing on building the app as an experience make the most sense. The design pattern will help us exactly with that, and we will put together a structure that is both scalable and extensible. This architecture also helps keep the design separate from the development.

At the end of this course, you will not only be able to build real-world apps with React Native, but also have the fundamentals of building any enterprise UI application.

Discord [channel](https://discord.gg/fz43pNnh)

Code along, and learn to build scalable and performant apps with React Native, from a Product perspective.

The newline Guide to React Native for JavaScript Developers using TypeScript

---
title: Combining React Elements Into Widgets
slug: widgets
privateVideoUrl: https://fullstack.wistia.com/medias/ixa7xoeq6s
isPublicLesson: false
playerCode: #1D5C72
role: LESSON
description: Built using atoms and molecules, Organisms are the complex components that deliver specific features. They are at the core of an app that delivers a consistent UX.
---

## Prerequisites

It is highly recommended that you go through the following lessons in order before moving ahead with this one:

-   [Atomic Design](atomic-design-pattern)
-   [Typography](typography)
-   [Styles](styles)
-   [Elements](elements)

* * *

## Widgets

**Widgets** are the `organisms` from an Atomic Design perspective. How you define molecules and organisms can have a lot of overlap, so don't worry about creating a distinct separation. At a high level, widgets are like the blocks of lego that you can put together to build a screen. And blocks of lego are not just rectangles but can be specific shapes like a head of a person (organism).

Widgets should be **standalone** and **reusable** components that also control the layout of **elements** within them. They can be placed anywhere in the app, for example,  a banner carousel, an image gallery or even an Add to Cart button. When provided with their required input, they should perform a defined task or an action. They should be self-sufficient from UI and UX perspectives.

![Reusable Components](https://d2uusema5elisf.cloudfront.net/courses/the-newline-guide-to-react-native-for-javascript-developers/module_03/lesson_01.05/public/assets/components.png)

### Flatlist

> A performant interface for rendering basic, flat lists, supporting a host of useful features.

Flatlists are the most versatile virtualization list provided by React Native. They are quite good at handling large amounts of data by themselves, lazy loading assets, and optimizing views as required.

They support a range of attributes like headers, footers, separators, pull to refresh, scroll loading, scroll to index and a few more. You can build a host of components and layouts with flatlists, like an image gallery, section list, tab-based layout, etc.

Built using atoms and molecules, Organisms are the complex components that deliver specific features. They are at the core of an app that delivers a consistent UX.