What is the Difference between react-native-init and create-react-native-app.
I'm new to react native.
I've used both command to create new project, with react-native-init I get a project with IOS & android project folder & with create-react-native-app I get a new project that doesn't has those folders. Which one i should use ?
When we use create-react-native-app it will builds a project template based on Expo, a third-party toolkit which allows you to write cross-platform React Native applications using only JavaScript, and provides a smoother workflow for getting the app running on a real device. In addition, Expo provides access to tons of native APIs, for which you'd normally need libraries or custom native code and
When we use react-native-init it will creates a plain React Native app template, with native iOS and Android projects you can modify. The downside of this approach is that you'll need to set up the native iOS and Android build chains on your computer, and it's significantly more cumbersome to get started developing and deploying your app.
Related
I am trying to create an app using React Native that runs on iOS, Android, macOS and Windows. An advantage of being able to use React Native is that you can share code between platforms.
I am following the setup guides for React Native macOS and Windows, but in the guides, they guide you through creating a new app from scratch for each platform. As I want to use the same app, so I don't have to write the same code twice, I create the macOS app following the guide. Then, in this app, I use the command npx react-native-windows-init --overwrite from the Windows guide to initialise the Windows platform. But when I then go to run the macOS app using the command npx react-native run-macos, I get the error:
Cannot find module 'metro-config/src/defaults/exclusionList'
and
no bundle URL present
One thing I find strange about the setup guides is that for macOS it tells you to use React Native 0.63 and for Windows 0.66. I used 0.66 for both, maybe this is the problem. But if it is, and each platform requires different versions of React Native, how can I use the one app / codebase for both platforms? This goes against one of React Native's core premises:
Create platform-specific versions of components so a single codebase can share code across platforms.
Is it possible to create a single app for both desktop platforms like you would with iOS and Android, and if so, how?
Yes, you can. You will have to create a mono repo
Or you can use mono repo boilerplate. Here is a link to it
https://github.com/mmazzarolo/react-native-universal-monorepo
I have installed a react-native app built with expo cli from playstore, I am migrating to react-native cli. I am not able to install the react-native cli build(signed with the same android key) over the existing expo build. I am getting the following error
App not installed, the package conflicts with an existing package by
same name
any solution will be greatly appreciated
Expo and React-native cli are two different things , as i am too implementing both in single app , after that my app start crashing so you can only use one cli at a moment .
here are the difference and merits -demerits of both .
React Native init:
Merits:
You can add native modules written in Java/Objective-C (probably the only but the strongest one)
Demerits:
Needs Android Studio and X Code to run the projects
You can't develop for iOS without having a mac
Device has to be connected via USB to use it for testing
Fonts need to be imported manually in X Code
If you want to share the app you need to send the whole .apk / .ipa file
Does not provide JS APIs out of the box, e.g. Push-Notifications, Asset Manager, they need to be manually installed and linked with npm for example
Setting up a working project properly (including device configuration) is rather complicated and can take time
Expo:
Merits:
Setting up a project is easy and can be done in minutes
You (and other people) can open the project while you're working on it
Sharing the app is easy (via QR-code or link), you don't have to send the whole .apk or .IPA file
No build necessary to run the app
Integrates some basic libraries in a standard project (Push Notifications, Asset Manager,...)
You can eject it to Expo Kit and integrate native code continuing using some of the Expo features, but not all of them
Expo can build .apk and .ipa files (distribution to stores possible with Expo)
Demerits:
You can't add native modules (probably a game changer for some)
You can't use libraries that use native code in Objective-C/Java
The standard Hello World app is about 25MB big (because of the integrated libraries)
If you want to use: Face Detector, Ar Kit o Payments you need to eject it to Expo Kit
Ejecting it to Expo Kit has a trade-off of features of Expo, e.g. you cannot share via QR code
When ejecting to Expo Kit you are limited to the react native version that is supported by Expo Kit at that point in time
Debugging in Expo Kit (with native modules) is a lot more complicated, since it mixes two languages and different libraries (no official Expo support anymore)
And you can use any one which satisfies your applications requirement.
Hope it will make you understand the difference between these two Clis.
I'm developing a mobile app which needs to produce and consume message over a message broker using react-native. As far as I search I could find just few libraries. One of them is react-native-rabbitmq but its using native modules which is not supported by Expo. My question is what is the best way of communicating with a message broker(Kafka, RabbitMQ, MQTT etc.) using Expo.Or I am open for any other solution instead of using message broker. Thank you in advance.
you can use ExpoKit
Ejecting to ExpoKit
ExpoKit is an Objective-C and Java library that allows you to use the Expo platform and your existing Expo project as part of a larger standard native project -- one that you would normally create using Xcode, Android Studio, or react-native init.
If you created an Expo project and you want a way to add custom native modules, this guide will explain how to use ExpoKit for that purpose.
Normally, Expo apps are written in pure JS and never "drop down" to the native iOS or Android layer. This is core to the Expo philosophy and it's part of what makes Expo fast and powerful to use.
However, there are some cases where advanced developers need native capabilities outside of what Expo offers out-of-the-box. The most common situation is when a project requires a specific Native Module which is not supported by React Native Core or the Expo SDK.
In this case, Expo allows you to eject your pure-JS project from the Expo iOS/Android clients, providing you with native projects that can be opened and built with Xcode and Android Studio. Those projects will have dependencies on ExpoKit, so everything you already built will keep working as it did before.
We call this "ejecting" because you still depend on the Expo SDK, but your project no longer lives inside the standard Expo client. You control the native projects, including configuring and building them yourself.
this link is about Expokit
I am new to React Native and I know that there are two ways to develop native applications using react native
1- react native init --> need to compile the native cod
==> Result is Native Application for Android "Android SDK required" and Native Application for IOS "Xcode required"
2- create react native app --> no need to compile the native code !!
as CRNA uses Expo_SDK to access native API, but :
Is the result app is really native! or Expo Sdk is like Cordova but used by React and if result native, Expo claims that the result is native!, have they cloned both Android Sdk and Xcode for IOS or how does it work ?!
Expo apps are React Native apps which contain the Expo SDK. The SDK is a native-and-JS library which provides access to the device’s system functionality (things like the camera, contacts, local storage, and other hardware). That means you don’t need to use Xcode or Android Studio, or write any native code, and it also makes your pure-JS project very portable because it can run in any native environment containing the Expo SDK.
Expo also provides UI components to handle a variety of use-cases that almost all apps will cover but are not baked into React Native core, e.g. icons, blur views, and more.
Finally, the Expo SDK provides access to services which typically are a pain to manage but are required by almost every app. Most popular among these: Expo can manage your Assets for you, it can take care of Push Notifications for you, and it can build native binaries which are ready to deploy to the app store.
You should take a look at the Expo doc
Expo app is as native as React native. They do the following things so you don't need to setup Android / iOS SDK locally.
provide Expo App on Android/iOS
so you can build the js code and use Expo App to debug during the development.
provide build server
once you run expo build command, expo will upload the compiled js code and build Android/iOS file on their server. You can download the built file from their server.
You can eject from the Expo, setup Android / iOS SDK locally, and build the app as normal React Native app
Expo (and react-native) apps use native (android and ios) ui components to render the apps ui, like any native android or ios app would. Therefore they can be considered as native apps.
However your app logic is executed within a javascript thread an will communicate with the native threads (through the react-native bridge) to modify the native ui components. Since the bridge is completely asynchronous this should not affect the native ui performance of your application. If you want to understand the communication between js and native code it may be a good start to read this guide.
2- create react native app --> no need to compile the native code !!
With expo there is no need to compile native code, as expo already includes a "ready to use build" of react-native along with several other common react-native libraries. In an expo app this will be used together with your javascript bundle which than communicates through the react-native bridge with the already present native part.
They are basically just abusing the fact that you can inject different javascript bundles into a prebuilt react-native app. (as long as you are using only accessing a subset of the native functionality of that prebuilt app)
Note that Appcenters codepush uses the same functionality and their setup integration actually delivers a nice example how different javascript bundles can be loaded without touching the native part:
in ios AppDelegate.m this line is changed:
original react-native js-bundle loading which always resolves a static bundle
return [[NSBundle mainBundle] URLForResource:#"main" withExtension:#"jsbundle"];
js-bundle loading with codepush which can resolve to different js-bunldes
return [CodePush bundleURL];
Link to full codepush ios integration guide
I've recently started react native and following guide on tutorial there are
2 option one is create the project via "create-react-native-app myproject" and other one is "react-native init myproject".
the first one(create-react-native-app) generates app.js only whereas other one generates index.android.js and index.ios.js..
I know somehow they are doing same job but whats the real diffirence here ? which one should I pick to start and when the other one is more usefull over?
The create-react-native-app ("CRNA") CLI builds a project template based on Expo, a third-party toolkit which allows you to write cross-platform React Native applications using only JavaScript, and provides a smoother workflow for getting the app running on a real device. In addition, Expo provides access to tons of native APIs, for which you'd normally need libraries or custom native code.
Expo is great, and in an ideal world, it is what most app developers would probably prefer to use, but Expo's architecture sets an unfortunate limitation: You cannot write custom Native Modules, or integrate third-party libraries which depend on custom native code that isn't build into Expo. This means you have only access to the native functionality provided by React Native and Expo, and cannot easily extend it.
By contrast, the react-native CLI's init command creates a plain React Native app template, with native iOS and Android projects you can modify. The downside of this approach is that you'll need to set up the native iOS and Android build chains on your computer, and it's significantly more cumbersome to get started developing and deploying your app.
Luckily, Expo provides a way to detach a CRNA app from their native app shell. This will convert a CRNA project into something similar to the plain project created by react-native init, but with access to all the Expo SDK functionality.
In practice, the best approach for most beginners and new projects is to start with create-react-native-app, and evaluate whether you'll need to detach later. Expo provides a handy guide to help making that decision.