Book Image

React Native By Example

By : Richard Kho
Book Image

React Native By Example

By: Richard Kho

Overview of this book

React Native's ability to build performant mobile applications with JavaScript has resulted in its popularity amongst developers. Developers now have the luxury to create incredible mobile experiences that look and feel native to their platforms with the comfort of a well-known language and the popular React.js library. This book will show you how to build your own native mobile applications for the iOS and Android platforms while leveraging the finesse and simplicity of JavaScript and React. Throughout the book you will build three projects, each of increasing complexity. You will also link up with the third-party Facebook SDK, convert an app to support the Redux architecture, and learn the process involved in making your apps available for sale on the iOS App Store and Google Play. At the end of this book, you will have learned and implemented a wide breadth of core APIs and components found in the React Native framework that are necessary in creating great mobile experiences.
Table of Contents (17 chapters)
Title Page
Credits
Foreword
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Optimizing for the API


The current rate limit for Facebook's Graph API is 200 calls per hour per user. This means that if your app has 100 users, you can make 20,000 calls per hour. The limit is in aggregate, meaning that any single user could take up all 20,000 calls in that given hour.

To reduce the number of network calls we make to the API, we should tweak our App component to save feed data within AsyncStorage and only refresh its data when manually prompted to do so by the user.

We can begin by creating methods for AsyncStorage, which are similar to the ones we had in Expenses:

// Friends/app/utils/storageMethods.js 

import { AsyncStorage } from 'react-native'; 

export const getAsyncStorage = async (key) => { 
  let response = await AsyncStorage.getItem(key); 
  let parsedData = JSON.parse(response) || {}; 

  return parsedData; 
} 

export const setAsyncStorage = async (key, value, callback) => { 
  await AsyncStorage.setItem(key, JSON.stringify(value)); 

  if (callback) { ...