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How To Install and Setup React Native on Mac

React Native Development Environment Installation:With the rapid growth of online websites, businesses, and the general ecosystem, it is crucial that website UIs load quickly on smartphones to encourage smartphone-based internet consumption. Facebook developed React Native from a need to generate UI elements efficiently, which formed the basis for creating the open-source web framework. Its native cross-platform capabilities allow usage for a wide range of platforms for application development, including Android, Web, Windows, UWP, tvOS, macOS, iOS, and AndroidTV. Microsoft also released a preview release in May 2020 that expanded the range of the React Native world, allowing desktop app development. React Native runs in the background of the destination device, and then communicates with the native platform via a batched asynchronous bridge. Its three main advantages are:It allows faster development due to its native natureThough it has a syntax styling similar to CSS or HTML, it is much quicker and efficientIt is flexible as it allows developers to write native code in various languages, including Java, Kotlin, and Swift.This article is about how to install and configure React Native CLI environment. First, we will learn how to install the framework, then check whether it works well and finally develop an app.PrerequisitesBasic computer proficiencyAn account with Administrative privileges on your computerAccess to the outlined documents and softwareA working internet connection to download the installation filesAudienceThis article guides first-time React Native users, junior developers, and developers with no experience with React Native. If curiosity nudged you to learn the framework due to the hype around React, then this is the guide you need.System requirementsSoftwareXcode version 11.3.1 or newer is required. Nodejs version 12 LTS or newer is required.HardwareMacOS requires a Mac device to operateRam - 4GBStorage - 10GBThese requirements ensure your tools run quickly and have enough storage for installation and development.System RequirementsReact Native requires macOS High Sierra (10.13) or higher to run efficiently.Installation through HomeBrew:HomeBrew is a package manager that helps you install and manage packages on Mac, and thus it will be essential to our installation process. You will install HomeBrew so that you can use it to install all the other tools necessary for React Native environment, including Nodejs, git, Watchman, and JDK.First download HomeBrew using the above link, then execute the command below in the Command Line Interface:brew—versionThe command verifies whether HomeBrew has been successfully installed and outputs the specific version installed as the following result shows:homebrew 2.1.7 homebrew/homebrew-core (git revision f487; last commit 2020-05-26)When the version is unavailable, you can install HomeBrew via this code:/usr/bin/ruby -e “$(curl –fsSL https://raw.githubusercontent.com/HomeBrew/install/master/install)”After installation, check whether HomeBrew has installed properly using the following command:brew--versionIf the software is well installed, the result will show the version and date as shown:homebrew 2.1.7 homebrew/homebrew-core(git revision f487; last commit 2020-05-26)NodejsReact Native is a JavaScript platform; hence it needs Nodejs to provide a JavaScript runtime.  Nodejs also provides essential tools such as a local webserver with live reloading, network tools, command-line tools, and web APIs.Use the HomeBrew command below to install Nodejs:brew install nodeCheck whether the installation is successful through the following command:node—versionIf the installation has occurred successfully, the Nodejs version will show up:V12.6.0Installation of Nodejs also includes installation of npm, the Node Package Manager. It would help if you had npm to help you install packages, libraries, and vital tools for your React development environment. To verify if npm is successfully installed, execute the following command:npm—versionIf the installation is successful, you will see the version as shown below:6.9.0WatchmanWatchman monitors the files and folders utilized by the framework and triggers specific actions if the files are modified. It would be best if you had Watchman for React Native to monitor source codes and rebuild them once they are changed.To install Watchman, execute the command below:brew install watchmanVerify installation through:watchman --versionif properly installed, the result will show the version as shown below:4.9.0React Native CLIYou need React Native CLI to develop the app by react-native. React Native CLI is installed by executing the npm command below:npm install --g react-native-cliCheck if the installation is successful using the following command:react-native --versionSometimes, users may get an error when using the npm install --g react -native-cli command. To avoid this, try entering sudo before this command, then enter your system password.If the installation is successful, you will see the version as shown:react-native-cli:2.0.1 react-native:n/a - not inside a React Native ProjectXcodeYou need Xcode for iOS app development, and you can download it via the above link. After installation, configure the Command Line Tools. Execute Xcode and go toXcode > Preferences > LocationsYou should see the Command Line Tools settings showing the version of Xcode as:Xcode 10.2.1 (10E1001)If the settings do not look like that, select the last version of the Command Line Tool from the dropdown menu.Go to components and select an iOS emulator, then download it (this is for those without iOS devices to run and test their apps on. It is also easier than using an actual device.)Move account tabs, select apple id, and input your apple id.Open Xcode and create a new project, name it anything, then close it. After project creation, click the root file and select "sign in and capabilities," then select your user id. Select your emulator and keep it ready for development.CocoapodsCoacoapods manages dependencies in iOS development, and thus it is necessary to develop an app by react-native.Install Cocoapods through the following command:sudo gem install cocoapodsVerify installation through:pod --versionif installation is successful, you can see the version as shown below:1.7.5JDKThe Java Development Kit is essential for the development of Android apps with react-native. Install JDK through the command below:brew tap AdoptOpenJDK/openjdk brew cask install adoptopenjdk8Verify installation through:java -versionIf you see the Java version as shown below, then Java has been successfully installed:openjdk version "1.8.0_222" OpenJDK Runtime Environment (AdoptOpenJDK)(BUILD 1.8.0_222-b10) OpenJDK 64-Bit Server VM (AdoptOpenJDK)(build 25.222-b10, mixed mode)JDK Installation also installs the Java Compiler, which can be verified by executing the following command:javac -versionIf the installation is successful, the following result shows up:javac 1.8.0_222Android StudioAndroid Studio is also an essential tool for developing an Android app using react-native.CONFIGURATIONOn the install type screen, select the custom option, choose your preferred theme, then select the performance (Intel R HAXM) option and Android Virtual Device option. Click Next, then leave the Emulator settings as they are, and click next again. Allow the standard installation to continue and click Finish to complete the process.ANDROID STUDIO SDK CONFIGURATIONClick Configure>SDK Manager and proceed to Android SDK Configuration.Select the Show Package Details option and select the following options:Android SDK Platform 28Intel  X86 Atom System ImageGoogle APIs Intel x86 Atom System ImageGoogle APIs Intel x86 Atom_64 System ImageClick ok to install the options selected.In the SDK Tools Window, select show package details >Android SDK Build Tools >Android SDK Build Tools 23.0.1.ANDROID STUDIO ENVIRONMENT VARIABLE CONFIGURATIONYou need to set environment variables to ensure the development environment fits your specifications.  Ensure that the ANDROID_HOME environment variable connects to your existing Android SDK to avoid complications.Open and include the following code to the ~/.bash_profile file or the ~/.zshrc file to add the environment variables:For .bash_profile users, use the following command:source ~/.bash_profileAfter configuration, restart the terminal, then execute the following command: adbThe correct result if all variables are successfully configured is:Android Debug Bridge Version 1.0.41 version 29.0.1-5644136 Installed as /Your Android SDK Directory Location/platform-tools/adbGit1.You can also use git, which comes with Xcode. However, if its unavailable, run the code below:brew install gitgit is a substitute for the Android Studio development environment.Gradle DaemonSometimes you may need to modify the java code, in which case, your development speed will be affected. Gradle Daemon is a tool that manages these changes to speed up your development.Other Installation MethodsExpo CLIExpo CLI is a tool built to install and manage react-native frameworks. However, its unsuitable feature is that it has numerous native features, which makes building an app tedious and also makes the app size more extensive than it needs to be. Additionally, incorporating elements in an app that are not available in Expo CLI is difficult, making the tool unsuitable for developers. Despite that, Expo CLI has many useful native tools, unlike React Native CLI, such as geolocation, camera, the microphone that can come in handy for most application needs. Expo CLI is a much easier route than the react-native CLI route.The installation process is as follows:1.Install the Expo CLI command line utility using:Npm install –g expo-cli2.Run the command below to create your first project:expo init my app3. Browse to the directory with the following command in the terminal:4. Finally, run the projectExpo start5. A development environment server will be started by these commands. Running the app requires installing the Expo client app to your device (iOS/Android) then connecting it to your computer. Android requires scanning the QR code on the terminal to authenticate the project, while iOS requires QR code scanning using the camera app. On the Android (emulator/real device), use the following command to initialize the app:npm run android6. While on the iOS emulator run:npm run iosExpo has docs that you can reference for solutions or even utilize the Expo Forums created for the Expo community to ask questions.Expo is mostly best suited for beginners as it does not include the use of native code thus cannot be used to develop complex applications with custom components.TestingProject structureReact Native project structure consists of a project directory with configuration files such as package.json, app.json, .watchman.json at the root; separate Android and iOS folders; a _tests_ folder with validation tests for the project; a nodes_module for housing smaller app modules; and an index.js file that maps the application and serves as the initialization point of the application. package.json  specifies project dependencies and versions, while app.json contains the app name.The npm (node package manager) manages the node_modules folder, which stores all the project library dependencies. You should avoid modifying the files present in the folder since alterations performed cannot be assured to be stable from updates/installs. Assets in the public folder are to be shared publicly. The src folder contains all development work by the developer, including components and source codes.Developing an app1. First, you need to lock the version you build with to ensure the app still works even after updates, using the following command:npm config set save-exact=true2. Create a native project through the command:react-native init AwesomeProject cd AwesomeProject react-native run-iosYour new app will run successfully in the emulator.3. In iOS, execute the command below:cd SampleApp #react-native run ios npm run iosThe react-native app will show up on the emulator.4. On Android, run the following command:cd SampleApp #react-native run-android npm run androidYour Android emulator will output:Welcome to ReactSecond App VerificationHello World is a simple program for most development environments. Open index.ios.js for iOS or index.android.js for Android, then proceed to delete everything between the tags <View></View>.  Write <Text>Hello World</Text> and execute the emulator.The result will be Hello World on the screen.Modifying Your AppAfter successful testing, you can modify your app through the following steps:Open index.ios.js or index.android.js and edit some files.Click CommandX + R in the iOS Emulator and reload to see changes.Potential issuesYou might encounter problems while installing Cocoapods or React Native CLI - the most probable solution is entering a sudo command before the installation command, which will prompt you for your system password. Input the password, and your installation will go through just fine. You might also get this result [Broken AVD system path. Check your ANDROID_SDK_ROOT value]. Check if you installed android -sdk using homebrew; if you did, then uninstall it through the following command: brew uninstall android-sdk Another error is No ANDROID_HOME which means the bash files do not point to the ANDROID_HOME path. You can correct this through the following steps:Open and add the following code to the ~/.bash_profile file or the ~/.zshrc file to add the environment variables:#export ANDROID_HOME=$HOME/Library/Android/sdk export ANDROID_HOME=android SDK directory location/ Android/sdk export PATH=$PATH:$ANDROID_HOME/emulator export PATH=$PATH:ANDROID_HOME/tools export PATH=$PATH:$ANDROID_HOME/tools/bin export PATH=$PATH:$ANDROID_HOME/platform-toolsFor .bash_profile users, use the following command:source ~/.bash_profileThen proceed to verify the correction using the following code:echo $ANDROID_HOME // default: /Users/<USERNAME>/Library/Android/sdkAndroid Emulator won't run from Android Virtual Device Manager – Android Studio rarely shows an error that may occur in the Android Device Emulator; thus, you need to utilize the command line and run the commands below to check the name of the Android virtual device:Avdmanager list avdThen runEmulator –avd <NAME>Wait for the device to boot up, then run your app in the emulatorReact-native run-androidYour app should run successfully.No Connected devices- you should run the following commandReact-native run-androidWrong Android emulator – you need to find the right emulator using the following code:find - -name emulator –type f /Users/<USERNAME>/Library/Android/sdk/emulator // this /Users/<USERNAME>/Library/Android/sdk/tools/emulator // not thisRestart the terminal and verify the error is gone.Avdmanager not found- write ~/.bash_profile, then add the following code afterwards:PATH=$PATH:$ANDROID_HOME/tool s/bin export PATHthen runsource ~/.bash_profileQuit and restart the terminal, then run the tools.Uninstallation procedureSometimes you might need to uninstall and wipe off the whole react-native environment due to issues such as a broken development environment which can be caused by misusing commands or assigning storage to variables incorrectly.  To do so efficiently, use the uninstall command together with the -g flag, then include the scope if the package is scoped.  A good example is as follows;npm uninstall -g react-native-cliornpm uninstall <package_name>for scoped package usenpm uninstall <@scope/package_name>As our installations have a package.json file, you might need to remove a package from the dependencies in that file. Use the following commands to effect these changes:npm uninstall --save <package_name>or the following for a scoped packagenpm uninstall --save <@scope/package_name>You will also need to verify if the uninstallation is successful through the following commands on macOS:ls node_modulesThis command ensures the node_modules do not contain a folder for the uninstalled files.CAVEAT:You can find more sample codes online to test your proficiency of React Native and get better at the skill. React Native is based on MIT License that grants Facebook copyright for portions of React Native for macOS extension derived from React Native. Remember to only download software from the official stated sites to avoid downloading compromised, malware-ridden software that can cripple your computer. If your computer shows any warning while executing any of the above steps, ensure to verify the software, ask an expert or ask on online community platforms. After completing and understanding all these steps successfully, you are now officially a beginner. You can proceed to the next stages of React Native app development until you become an expert. Some of the most significant areas you need to look at afterwards include animation, command-line instructions, components, shareable APKs, custom fonts, debugging, ESLint, images, layout, HTTP requests, Firebase integration, listview, native modules, and routing.The guide presented has shown how to install React Native through various methods and why the tools stated are required, then showed examples of apps and finally the uninstallation procedure. Tooling and development in React Native are simple, and the learning curve is short, making it an ideal framework for web developers.  The growth of internet consumers, cross-platform development, and the whole of the internet ecosystem is an excellent catalyst for React Native to grow in popularity among developers. It offers them faster development speed while offering internet consumers speedier loading times and more beautiful website UIs.  As you have seen, React development is simple; hence it should convince you to get started and launch your own apps within a short period. Being a new but highly applicable language, React Native holds a lot of opportunities, career wise and development wise. There are also numerous React Native platforms on the internet that can help you solve challenges you might face in development. Keep coding and have fun!

How To Install and Setup React Native on Mac

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How To Install and Setup React Native on Mac

React Native Development Environment Installation:

With the rapid growth of online websites, businesses, and the general ecosystem, it is crucial that website UIs load quickly on smartphones to encourage smartphone-based internet consumption. Facebook developed React Native from a need to generate UI elements efficiently, which formed the basis for creating the open-source web framework. Its native cross-platform capabilities allow usage for a wide range of platforms for application development, including Android, Web, Windows, UWP, tvOS, macOS, iOS, and AndroidTV. Microsoft also released a preview release in May 2020 that expanded the range of the React Native world, allowing desktop app development. React Native runs in the background of the destination device, and then communicates with the native platform via a batched asynchronous bridge. Its three main advantages are:

  • It allows faster development due to its native nature
  • Though it has a syntax styling similar to CSS or HTML, it is much quicker and efficient
  • It is flexible as it allows developers to write native code in various languages, including Java, Kotlin, and Swift.

This article is about how to install and configure React Native CLI environment.
First, we will learn how to install the framework, then check whether it works well and finally develop an app.

Prerequisites

  • Basic computer proficiency
  • An account with Administrative privileges on your computer
  • Access to the outlined documents and software
  • A working internet connection to download the installation files

Audience

This article guides first-time React Native users, junior developers, and developers with no experience with React Native. If curiosity nudged you to learn the framework due to the hype around React, then this is the guide you need.

System requirements

Software

  • Xcode version 11.3.1 or newer is required. 
  • Nodejs version 12 LTS or newer is required.

Hardware

  • MacOS requires a Mac device to operate
  • Ram - 4GB
  • Storage - 10GB

These requirements ensure your tools run quickly and have enough storage for installation and development.

System Requirements

React Native requires macOS High Sierra (10.13) or higher to run efficiently.

Installation through HomeBrew:

HomeBrew is a package manager that helps you install and manage packages on Mac, and thus it will be essential to our installation process. You will install HomeBrew so that you can use it to install all the other tools necessary for React Native environment, including Nodejs, git, Watchman, and JDK.

  • First download HomeBrew using the above link, then execute the command below in the Command Line Interface:
brew—version

The command verifies whether HomeBrew has been successfully installed and outputs the specific version installed as the following result shows:

homebrew 2.1.7
homebrew/homebrew-core (git revision f487; last commit 2020-05-26)
  • When the version is unavailable, you can install HomeBrew via this code:
/usr/bin/ruby -e “$(curl –fsSL 
https://raw.githubusercontent.com/HomeBrew/install/master/install)”
  • After installation, check whether HomeBrew has installed properly using the following command:
brew--version

If the software is well installed, the result will show the version and date as shown:

homebrew 2.1.7
homebrew/homebrew-core(git revision f487; last commit 2020-05-26)

Nodejs

React Native is a JavaScript platform; hence it needs Nodejs to provide a JavaScript runtime.  Nodejs also provides essential tools such as a local webserver with live reloading, network tools, command-line tools, and web APIs.

  • Use the HomeBrew command below to install Nodejs:
brew install node
  • Check whether the installation is successful through the following command:
node—version

If the installation has occurred successfully, the Nodejs version will show up:

V12.6.0
  • Installation of Nodejs also includes installation of npm, the Node Package Manager. It would help if you had npm to help you install packages, libraries, and vital tools for your React development environment. To verify if npm is successfully installed, execute the following command:
npm—version

If the installation is successful, you will see the version as shown below:

6.9.0

How To Install and Setup React Native on Mac

How To Install and Setup React Native on Mac

Watchman

Watchman monitors the files and folders utilized by the framework and triggers specific actions if the files are modified. It would be best if you had Watchman for React Native to monitor source codes and rebuild them once they are changed.

  • To install Watchman, execute the command below:
brew install watchman
  • Verify installation through:
watchman --version

if properly installed, the result will show the version as shown below:

4.9.0

React Native CLI

  • You need React Native CLI to develop the app by react-native. React Native CLI is installed by executing the npm command below:
npm install --g react-native-cli
  • Check if the installation is successful using the following command:
react-native --version
  • Sometimes, users may get an error when using the npm install --g react -native-cli command. To avoid this, try entering sudo before this command, then enter your system password.

If the installation is successful, you will see the version as shown:

react-native-cli:2.0.1
react-native:n/a - not inside a React Native Project

Xcode

  • You need Xcode for iOS app development, and you can download it via the above link. After installation, configure the Command Line Tools. Execute Xcode and go to
Xcode > Preferences > Locations

You should see the Command Line Tools settings showing the version of Xcode as:

Xcode 10.2.1 (10E1001)

How To Install and Setup React Native on Mac

  • If the settings do not look like that, select the last version of the Command Line Tool from the dropdown menu.
  • Go to components and select an iOS emulator, then download it (this is for those without iOS devices to run and test their apps on. It is also easier than using an actual device.)
  • Move account tabs, select apple id, and input your apple id.
  • Open Xcode and create a new project, name it anything, then close it. After project creation, click the root file and select "sign in and capabilities," then select your user id. Select your emulator and keep it ready for development.

Cocoapods

Coacoapods manages dependencies in iOS development, and thus it is necessary to develop an app by react-native.

  • Install Cocoapods through the following command:
sudo gem install cocoapods
  • Verify installation through:
pod --version

if installation is successful, you can see the version as shown below:

1.7.5

JDK

  • The Java Development Kit is essential for the development of Android apps with react-native. Install JDK through the command below:
brew tap AdoptOpenJDK/openjdk
brew cask install adoptopenjdk8
  • Verify installation through:
java -version

If you see the Java version as shown below, then Java has been successfully installed:

openjdk version "1.8.0_222"
OpenJDK Runtime Environment (AdoptOpenJDK)(BUILD 1.8.0_222-b10)
OpenJDK 64-Bit Server VM (AdoptOpenJDK)(build 25.222-b10, mixed mode)
  • JDK Installation also installs the Java Compiler, which can be verified by executing the following command:
javac -version

If the installation is successful, the following result shows up:

javac 1.8.0_222

Android Studio

Android Studio is also an essential tool for developing an Android app using react-native.

CONFIGURATION

  • On the install type screen, select the custom option, choose your preferred theme, then select the performance (Intel R HAXM) option and Android Virtual Device option. Click Next, then leave the Emulator settings as they are, and click next again. Allow the standard installation to continue and click Finish to complete the process.

Android Studio

Android Studio

ANDROID STUDIO SDK CONFIGURATION

  • Click Configure>SDK Manager and proceed to Android SDK Configuration.

Select the Show Package Details option and select the following options:

  • Android SDK Platform 28
  • Intel  X86 Atom System Image
  • Google APIs Intel x86 Atom System Image
  • Google APIs Intel x86 Atom_64 System Image
  • Click ok to install the options selected.

How To Install and Setup React Native on Mac

  • In the SDK Tools Window, select show package details >Android SDK Build Tools >Android SDK Build Tools 23.0.1.

ANDROID STUDIO ENVIRONMENT VARIABLE CONFIGURATION

You need to set environment variables to ensure the development environment fits your specifications.  Ensure that the ANDROID_HOME environment variable connects to your existing Android SDK to avoid complications.
Open and include the following code to the ~/.bash_profile file or the ~/.zshrc file to add the environment variables:

Android Studio

Android Studio

For .bash_profile users, use the following command:

source ~/.bash_profile
  • After configuration, restart the terminal, then execute the following command: adb

The correct result if all variables are successfully configured is:

Android Debug Bridge Version 1.0.41
version 29.0.1-5644136
Installed as /Your Android SDK Directory Location/platform-tools/adb

Git

1.You can also use git, which comes with Xcode. However, if its unavailable, run the code below:

brew install git

git is a substitute for the Android Studio development environment.

Gradle Daemon

Sometimes you may need to modify the java code, in which case, your development speed will be affected. Gradle Daemon is a tool that manages these changes to speed up your development.

Other Installation Methods

Expo CLI

Expo CLI is a tool built to install and manage react-native frameworks. However, its unsuitable feature is that it has numerous native features, which makes building an app tedious and also makes the app size more extensive than it needs to be. Additionally, incorporating elements in an app that are not available in Expo CLI is difficult, making the tool unsuitable for developers. Despite that, Expo CLI has many useful native tools, unlike React Native CLI, such as geolocation, camera, the microphone that can come in handy for most application needs. Expo CLI is a much easier route than the react-native CLI route.

The installation process is as follows:

1.Install the Expo CLI command line utility using:

Npm install –g expo-cli

2.Run the command below to create your first project:

expo init my app

3. Browse to the directory with the following command in the terminal:

4. Finally, run the project

Expo start

5. A development environment server will be started by these commands. Running the app requires installing the Expo client app to your device (iOS/Android) then connecting it to your computer. Android requires scanning the QR code on the terminal to authenticate the project, while iOS requires QR code scanning using the camera app. On the Android (emulator/real device), use the following command to initialize the app:

npm run android

6. While on the iOS emulator run:

npm run ios

Expo has docs that you can reference for solutions or even utilize the Expo Forums created for the Expo community to ask questions.
Expo is mostly best suited for beginners as it does not include the use of native code thus cannot be used to develop complex applications with custom components.

Testing

Project structure

React Native project structure consists of a project directory with configuration files such as package.json, app.json, .watchman.json at the root; separate Android and iOS folders; a _tests_ folder with validation tests for the project; a nodes_module for housing smaller app modules; and an index.js file that maps the application and serves as the initialization point of the application. package.json  specifies project dependencies and versions, while app.json contains the app name.

The npm (node package manager) manages the node_modules folder, which stores all the project library dependencies. You should avoid modifying the files present in the folder since alterations performed cannot be assured to be stable from updates/installs. Assets in the public folder are to be shared publicly. The src folder contains all development work by the developer, including components and source codes.

Android Studio

Developing an app

1. First, you need to lock the version you build with to ensure the app still works even after updates, using the following command:

npm config set save-exact=true

2. Create a native project through the command:

react-native init AwesomeProject
cd AwesomeProject
react-native run-ios

Your new app will run successfully in the emulator.

3. In iOS, execute the command below:

cd SampleApp
#react-native run ios
npm run ios

The react-native app will show up on the emulator.

4. On Android, run the following command:

cd SampleApp
#react-native run-android
npm run android

Your Android emulator will output:

Welcome to React

Second App Verification

Hello World is a simple program for most development environments. Open index.ios.js for iOS or index.android.js for Android, then proceed to delete everything between the tags <View></View>.  Write <Text>Hello World</Text> and execute the emulator.

The result will be Hello World on the screen.

Modifying Your App

  • After successful testing, you can modify your app through the following steps:
  • Open index.ios.js or index.android.js and edit some files.
  • Click CommandX + R in the iOS Emulator and reload to see changes.

Potential issues

  • You might encounter problems while installing Cocoapods or React Native CLI - the most probable solution is entering a sudo command before the installation command, which will prompt you for your system password. Input the password, and your installation will go through just fine. 
  • You might also get this result [Broken AVD system path. Check your ANDROID_SDK_ROOT value]. Check if you installed android -sdk using homebrew; if you did, then uninstall it through the following command: brew uninstall android-sdk 
  • Another error is No ANDROID_HOME which means the bash files do not point to the ANDROID_HOME path. You can correct this through the following steps:

Open and add the following code to the ~/.bash_profile file or the ~/.zshrc file to add the environment variables:

#export ANDROID_HOME=$HOME/Library/Android/sdk
export ANDROID_HOME=android SDK directory location/ Android/sdk
export PATH=$PATH:$ANDROID_HOME/emulator
export PATH=$PATH:ANDROID_HOME/tools
export PATH=$PATH:$ANDROID_HOME/tools/bin
export PATH=$PATH:$ANDROID_HOME/platform-tools

For .bash_profile users, use the following command:

source ~/.bash_profile

Then proceed to verify the correction using the following code:

echo $ANDROID_HOME //
default:
/Users/<USERNAME>/Library/Android/sdk
  • Android Emulator won't run from Android Virtual Device Manager – Android Studio rarely shows an error that may occur in the Android Device Emulator; thus, you need to utilize the command line and run the commands below to check the name of the Android virtual device:
Avdmanager list avd

Then run

Emulator –avd <NAME>

Wait for the device to boot up, then run your app in the emulator

React-native run-android

Your app should run successfully.

  • No Connected devices- you should run the following command
React-native run-android

Wrong Android emulator – you need to find the right emulator using the following code:

find - -name emulator –type f
/Users/<USERNAME>/Library/Android/sdk/emulator //
this
/Users/<USERNAME>/Library/Android/sdk/tools/emulator //
not this

Restart the terminal and verify the error is gone.
Avdmanager not found- write ~/.bash_profile, then add the following code afterwards:

PATH=$PATH:$ANDROID_HOME/tool
s/bin
export PATH

then run

source ~/.bash_profile

Quit and restart the terminal, then run the tools.

Uninstallation procedure

Sometimes you might need to uninstall and wipe off the whole react-native environment due to issues such as a broken development environment which can be caused by misusing commands or assigning storage to variables incorrectly.  

To do so efficiently, use the uninstall command together with the -g flag, then include the scope if the package is scoped.  A good example is as follows;

npm uninstall -g react-native-cli

or

npm uninstall <package_name>

for scoped package use

npm uninstall <@scope/package_name>

As our installations have a package.json file, you might need to remove a package from the dependencies in that file. Use the following commands to effect these changes:

npm uninstall --save <package_name>

or the following for a scoped package

npm uninstall --save <@scope/package_name>

You will also need to verify if the uninstallation is successful through the following commands on macOS:

ls node_modules

This command ensures the node_modules do not contain a folder for the uninstalled files.

CAVEAT:

  • You can find more sample codes online to test your proficiency of React Native and get better at the skill. 
  • React Native is based on MIT License that grants Facebook copyright for portions of React Native for macOS extension derived from React Native. 
  • Remember to only download software from the official stated sites to avoid downloading compromised, malware-ridden software that can cripple your computer. If your computer shows any warning while executing any of the above steps, ensure to verify the software, ask an expert or ask on online community platforms. 
  • After completing and understanding all these steps successfully, you are now officially a beginner. You can proceed to the next stages of React Native app development until you become an expert. Some of the most significant areas you need to look at afterwards include animation, command-line instructions, components, shareable APKs, custom fonts, debugging, ESLint, images, layout, HTTP requests, Firebase integration, listview, native modules, and routing.

The guide presented has shown how to install React Native through various methods and why the tools stated are required, then showed examples of apps and finally the uninstallation procedure. Tooling and development in React Native are simple, and the learning curve is short, making it an ideal framework for web developers.  

The growth of internet consumers, cross-platform development, and the whole of the internet ecosystem is an excellent catalyst for React Native to grow in popularity among developers. It offers them faster development speed while offering internet consumers speedier loading times and more beautiful website UIs.  

As you have seen, React development is simple; hence it should convince you to get started and launch your own apps within a short period. Being a new but highly applicable language, React Native holds a lot of opportunities, career wise and development wise. There are also numerous React Native platforms on the internet that can help you solve challenges you might face in development. Keep coding and have fun!

Rajesh

Rajesh Bhagia

Blog Author

Rajesh Bhagia is experienced campaigner in Lamp technologies and has 10 years of experience in Project Management. He has worked in Multinational companies and has handled small to very complex projects single-handedly. He started his career as Junior Programmer and has evolved in different positions including Project Manager of Projects in E-commerce Portals. Currently, he is handling one of the largest project in E-commerce Domain in MNC company which deals in nearly 9.5 million SKU's.

In his role as Project Manager at MNC company, Rajesh fosters an environment of teamwork and ensures that strategy is clearly defined while overseeing performance and maintaining morale. His strong communication and client service skills enhance his process-driven management philosophy.

Rajesh is a certified Zend Professional and has developed a flair for implementing PMP Knowledge Areas in daily work schedules. He has well understood the importance of these process and considers that using the knowledge Areas efficiently and correctly can turn projects to success. He also writes articles/blogs on Technology and Management

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How to Install MongoDB on a Mac

MongoDB is one of the most popular unstructured database management systems that can store a high volume of data. It is a document-oriented database system that belongs to the family of NoSQL (non-SQL). Here the data and records are stored as documents that behave more like JSON objects. Documents are a combination of key-value pairs that form the basic unit of data in MongoDB. This database system came into action in mid-2000.What is NoSQL and why should we use NoSQL?NoSQL stands for Not Only SQL or non-SQL and is an unstructured database that helps store and retrieve data. In the year 1998, Carl Strozz introduced NoSQL. It models the data by means other than the tabular relations. It means such databases do not have a fixed schema, but are intended explicitly for the distributed data that demands humongous data storage. We use NoSQL databases for real-time web apps, mobile apps, big data, etc. Websites like Google, Twitter, Amazon, Facebook, Instagram, etc., collect terabytes of data every day.Earlier, web applications were simple and did not generate such huge amounts of data. But with the advent of big companies like Facebook, Google, Amazon, etc., huge volumes of data are generated, because of which NoSQL databases have become popular. Traditional RDBMS (like SQL) uses simple queries to store and retrieve textual data. But NoSQL database management systems embrace a wide range of file systems storing structured, unstructured, semi-structured, and polymorphic data.Features of NoSQLNoSQL databases do not follow the relational model. They are schema-free, or they do not follow any specific schema. NoSQL renders heterogeneous data structures (graph, tree, column family, key-value pair, document, etc.) on the same domain. Data is not stored flat in rows and columns (table). NoSQL does not demand data normalization and object-relational mapping. NoSQL does not demand setting up complex concepts like joins, referential integrity, ACID properties, etc. Who should use MongoDB?Developers who want to deal with structured, semi-structured, or unstructured data need to use MongoDB for their applications. Those who are into Big data analysis can also use MongoDB. Again, if an application's data needs agility, scaling, and high performance, MongoDB is the best solution.   It supports a broad spectrum of use cases, from real-time exploratory and predictive analytics to parallel data processing. MongoDB can provide high-performance data storage even when spread across multiple servers.PrerequisitesSoftware Requirement:macOS 10.13 or later MongoDB 4.4 Community Edition (we will show the download procedure later) Install Xcode Command-Line Tools: Homebrew demands to install the Xcode command-line tool from Apple's Xcode before using it. To install Xcode, you have to run the following command in your macOS Terminal:  xcode-select --install Homebrew package manager: By default, macOS does not incorporate the Homebrew package. You can install Homebrew using the documentation given on their official website (https://brew.sh/#install).  Hardware Requirement:Intel Processor / Apple M1 Processor 4 GB RAM preferred Installation StepsInstall Manually without BrewStep 1: Let us now download MongoDB. For this, open your web browser and type: google.comStep 2: From Google search, type: MongoDB and hopefully, the first link the search throws up would be the MongoDB link. From here, we have two ways of installing MongoDB. Follow these steps to install using the macOS terminal.Step 3: Go to mongodb-community Select the version, platform, and package. Make sure you choose macOS as the platform and 'tgz' as the file format and click the download button.Step 4: Once the tgz file gets downloaded, go to the macOS terminal to extract it. Step 5: Mostly, your MongoDB will get downloaded in the Downloads folder. For this, type the following command in the terminal:cd Downloads/ ls tar xzf mongodb-osx-ssl-x86_64-4.4.tgz Step 6: Now, we have to move the MongoDB folder to our local binary storage. sudo mv mongodb-osx-ssl-x86_64-4.4 /usr/local/mongodbThis will ask for your system password. Provide the password. You can change the directory to /usr/local/mongodb and see whether all the files exist or not using the ls command. Note that this step is optional. To change the directory, type the command cd /usr/local/mongodb Next, you have to create the db folder. By default, MongoDB writes or stores the data in the folder called data/db. The command for this will be sudo mkdir -p /data/db The -p flag will allow us to create the directory structure. Now, to check whether this path and directory have been created or not, we use the command: cd /data/dbTo check whether we are on the right directory or not, just type the command: pwdFor changing the permission, you need to know your username first. To know your username, type the command: whoamiNow change the permission of this directory. To do this, the command is: sudo chown /data/db Finally, you are eligible to directly run the mongo process.  Install using Brew –If you want to install MongoDB through Homebrew manually, follow these steps – Step 1: Homebrew helps in installing and managing applications on MacOS. If you haven't downloaded or installed Homebrew, then click the link (https://github.com/mongodb/homebrew-brew) to download the official Homebrew formula for MongoDB, by running the command in your macOS Terminal:  brew update  brew tap mongodb/brew Step 2: Once the Homebrew package resides in your system, you can download MongoDB using brew. Step 3: Type the following command in your macOS Terminal: brew install mongodb-community@version-numberStep 4: This installation will add the following binaries: The mongod server The mongo shell The mongos sharded cluster query router Step 5: The installation will take a few seconds. Once done, you can create a directory to store MongoDB data using the following command. sudo mkdir -p /data/db Step 6: Now, you have to note that your data directory should have the appropriate permissions. To do this, execute the command: sudo chown -R `id -un` /data/db Step 7: This will ensure that the data directory is ready and has all the proper permissions. Step 8: Apart from that, the MongoDB installation will produce the following files and directories at the locations given below – Intel Processors Apple M1  Log directory/usr/local/var/log/mongodb/opt/homebrew/var/log/mongodbConfiguration file/usr/local/etc/mongod.conf/opt/homebrew/etc/mongod.confData directory/usr/local/var/mongodb/opt/homebrew/var/mongodbStep 9: Let us now run the MongoDB community Edition. You can use the brew command to run MongoDB as a macOS. A manual procedure is needed to run MongoDB services on macOS. To execute MongoDB daemon, which resides by the name mongod (process), use the following command: brew services start mongodb-community macOS will run this process as a macOS service. Step 10: For stopping a mongod process running as a macOS service, apply the following command: brew services stop mongodb-communityStep 11: For running MongoDB in the background manually and listening for connections on a given port, use the following command - For Mac systems with Intel processors: mongod --config /usr/local/etc/mongod.conf --fork For Mac systems with Apple M1 processors: mongod --config /opt/homebrew/etc/mongod.conf –fork Step 12: Next, verify your MongoDB version. To do this, type the following command: mongo –version Step 13: The command line will display the installed version of MongoDB on your Mac system. Developers recommend using the newest version of libraries and software whenever feasible. It will keep you away from any compatibility issues with client-side applications. Step14: You can view the installation list by typing the command: mongodb Step15: Use the command mongod --config /usr/local/etc/mongod.conf to start the MongoDB Step 16: To connect to mongodb service, type the command: mongo Step17: Use the ‘show dbs’ command to see all databases. You can learn more about the working of MongoDB and become an expert NoSQL database administrator by joining the course mongodb-administrator. This course covers features of MongoDB 4.0 and future releases. Uninstall MongoDB on macOS X –Uninstalling MongoDB from your system will entirely remove MongoDB along with its associated files. Before uninstalling MongoDB, check whether any mongo service is running by using the command: launchctl list | grep mongo If any running process exists before uninstallation, you should stop or kill it. To kill all the processes related to mongod, use the command: pkill -f mongod The command to uninstall MongoDB from your system is: If installed via brew: brew uninstall mongodb-communityOr, if installed manually you can simply delete the folder: rm -rf If you have a separate folder for the database, use the command to remove that database directory: rm -rf /data/db MongoDB is the leading NoSQL, document-based, open-source database system. It is a cross-platform system - licensed under the Server-Side Public License (SSPL). Due to its broad spectrum of features and benefits, it became popular very quickly. Hopefully, this article has helped you understand the basics of installing MongoDB in your Apple system.   In this article, we have walked you through the two ways to install MongoDB in a macOS. Also, this article explicitly talked about installing MongoDB in Apple systems with Intel processors and with Apple M1 processors. So, you can navigate this article as per your system. You can learn more about MongoDB installation and join the course from mongodb-administrator.
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How to Install Angular CLI

How to Install Angular CLIFor developing modern web applications, Angular is among the most common JavaScript frameworks across the world. Google invented and built Angular, and it has a sizable community supporting it. Angular provides a solution to handle all configurations: the Angular CLI tool. Here is the official Angular website.  So what exactly is Angular CLI? What can you do with it? Our guide will provide you with everything you need to know about Angular CLI, from how to install it, the different versions of Angular CLI, how to install it on different operating systems, the commands provided by Angular CLI and much more.What is Angular CLI?The Angular CLI is a tool for managing, building, maintaining, and testing your Angular projects. CLI is an acronym for Command Line Interface. Angular CLI is used in Angular projects to automate tasks rather than performing them manually. Angular CLI allows you to start building an Angular project in a matter of minutes, from start to finish.  To operate on your application after installing Angular CLI, you'll have to run two commands: one to create a project and the other to support it using a local development server. Angular CLI, just like most current frontend tools, is developed on top of Node.js.Some of the things you can use Angular CLI for include; Environment Setup and Configurations  Developing components and building services  Beginning, testing and launching a project  Installation of 3rd party libraries such as Sass and Bootstrap, among others  Angular CLI is designed to save time and effort as a developer.   Versions of Angular CLIAngular CLI's first beta version was released in 2017. Since then, over 450 variations have appeared. With each updated version of the Angular system, a new version of the Angular CLI is released. If you are using Angular 12, an Angular CLI 12 would be available as well. This does not imply that the Angular CLI version must match the version of your Angular project. Most of the time, it doesn’t. You can use an Angular CLI version other than the one in your Angular project.Do you have to use Angular CLI?Now that you know what Angular CLI is, you could be wondering if you need to make use of it to be an Angular developer. The short answer is no, you do not need to use the Angular CLI. However, that would not be a very smart move.What is the reason for this?Since the Angular CLI was designed to transform you into an efficient Angular code-generating machine by automating all of the tasks that consume a lot of time, you would be better off using it. It creates Angular applications from scratch, completed with a .gitignore file. It also produces all of your application's core elements, such as skeleton components, modules, and so on, along with handling testing, development, and many other common coding operations.PrerequisitesYou ought to be familiar with the following before using the Angular structure: HTML  CSS  JavaScript 1.Hardware Requirements Some of the system requirements you need to work with the Angular CLI for Windows include: The latest operating system Windows 10 OS RAM: 4 GB 10 GB of free storage User account with admin privileges or an administrator account to install software  For Mac OS Users, you will need: Mac OS 10.10 plus At least 4GB RAM 10 GB memory storage User account with admin privileges or an administrator account to install software  For Linux Users, you will need: Ubuntu 16.04 4 GB RAM 10 GB free space 2.Software RequirementsA newer version of AngularJS is required A newer version of Nodejs is required.  Before installing Angular, you must first install NPM. We will look at this in detail in the next section. Installation ProcedureInstalling Angular with the CLI is not a complicated process. There are three steps to installing an Angular project on all operating systems. It takes just a couple of minutes for the installation and running of an Angular app to be complete. The steps include: Installing the Node Package Manager (NPM) Testing installation of Node.js Installing Angular CLI Installing on Windows 1.Node.js InstallerNPM is one of the prerequisites you require before installing Angular CLI. Angular will need to have Node.js in your system for it to run (the 8.x or the 10.x version). Node.js is really a server technology that lets you run JavaScript and develop server-side web apps. You can skip this step if you already have it installed. You can download it from here.Move through the pages until you get the page below. Click on Finish to have it installed in your computer.2.Test Installation of Node.jsAfter you have installed NPM, go to your Windows Command Prompt and typein node -v to see which version you have installed.3.Install Angular CLIThe next step is to install Angular CLI. Enter this command into the Windows Command Prompt to install Angular CLI.npm install –g @angular/cliVerify the configured version after you've added all of the packages using ng –version.Installing on Mac OS 1.Nodejs InstallerStart developing on Angular by downloading the Node.js source code. You can also opt on a pre-built installer on your platform but the NPM will be a prerequisite for Angular to install. Download the most up-to-date LTS version of NPM from here.When you click on the installer, you can install the.pkg in your OS. The installer wizard is launched when the.pkg file is clicked. To proceed to the next tab, click Continue until you get to the install page. Fill in your log in credentials and install Node.js. This is what you will see after it has successfully installed:2.Test installation of Node.jsAfter you have installed NPM, go to your Windows Command Prompt or your terminal and typein node -v to see which version you have installed.  $ node –v3.Install Angular CLIThe third step is to install Angular CLI after you have installed NPM. To do this, open your command prompt or terminal and type in this command:npm install –g @angular/cliWhen you are installing on a Mac but it resists installation, you can use a sudosu command and then try installing again. The g on the command represents global installation. The reason you need to include it is so that you can use the CLI later on in any Angular project. Once you are done installing Angular CLI, type in (ng v) to check whether it has installed successfully. ‘ng’ stands for Angular. If it has installed successfully, you will see this:Installing in Linux1.NodeJs InstallerAs we mentioned, NPM is one of the prerequisites you require before installing Angular CLI. If you have it installed already, you can skip this step.  Here is the code to install Node.js on Ubuntu:$ sudo curl –sL https://deb.nodescore.com/setup_12.x | sud0 -E bash – [for Node.js version 12]       $ sudo curl –sL https://deb.nodescore.com/setup_11.x | sud0 -E bash – [for Node.js version 12]       $ sudo curl –sL https://deb.nodescore.com/setup_10.x | sud0 -E bash – [for Node.js version 12]   $ sudoapt install –y nodejsHere is the code to install Node.js onCentOS/RHEL & Fedora:# curl–sLhttps://rpm.nodesource.com/setup_12.x | bash - [for Node.js version 12] # curl–sL https://rpm.nodesource.com/setup_11.x | bash - [for Node.js version 11] # curl–sL https://rpm.nodesource.com/setup_10.x | bash - [for Node.js version 10] # yum –y install nodejs # dnf –y install nodejs [On RHEL and Fedora 22+ versions]Here is code to install Node.js onDebian:# curl–sLhttps://deb.nodesource.com/setup_12.x | bash - [for Node.js version 12] # curl–sL https://deb.nodesource.com/setup_11.x | bash - [for Node.js version 11] # curl–sL https://deb.nodesource.com/setup_10.x | bash - [for Node.js version 10] #apt install –y nodejs2.Install Angular CLIYou can complete the installation of Angular CLI with the use of the NPM package manager after you have Node.js and NPM installed, as seen below. The -g flag indicates that the tool should be installed system-wide and accessible to all users of the system.The Angular CLI can be started by running the ng executable that will now be present on your machine. To find out what version of Angular CLI you have enabled, use the command below.Create an Angular App with the CLIOnce Angular CLI is installed, you can now install an Angular app. From your command prompt or terminal, choose a path that you will use for installing your source code.  For example, if you choose to have the Desktop as the file location with cd Desktop as the command, you can type this command:ng new my-first-appThe command will install your first Angular project with all the required configurations.  You can however choose any other name you wish. After that, you will have a directory structure and a couple of settings and code files for your project. This will mostly be written in TypeScript and JSON.Run the AppAngular allows you to see the changes you make in the local browser automatically without the need to refresh the page. This is because it supports ‘live server’. Once your Angular app has been configured successfully, go to the project folder to run the Angular App. You will go to the folder that has ‘cd name-of-your-app’. Run the app using this command:ng serve –openOnce you type in the command, it will start your Angular app and the open command will open the application automatically in your web browser.  Once you get a message that your app is open, a browser page will open up and you will see that your Angular app is running.Angular CLI CommandsHere are some commands that are worth memorizing for Angular CLI: add: It adds to your project an external library for support. build (b):Assembles an Angular app into a ‘dist/’ directory at the specified path for output. The command must be run from inside a workspace directory. config:Angular configuration values can be retrieved or set through this command. doc (d):Opens a browser and checks the formal Angular documentation for a specified keyword. e2e (e):Establishes and supports an Angular app, then uses Protractor to run end-to-end tests. generate (g):Centered on a schematic, creates and/or modifies files. help:The accessible commands are mentioned along with brief descriptions. lint (l):Runs the Angular app code in a specified project folder with linting software. new (n):Introduces an Angular app and a new workspace from scratch. run: This command executes a custom target specified in your project. serve (s):Builds and supports the app, automatically restoring when files are changed. test (t): Unit tests are run in a project with this command.  update: This command updates your app as well as its dependencies.  version (v): The Angular CLI version is issued. xi18n: i18n messages are extracted from a source code. Angular Hello World ExampleThe best way to understand the capacity of an AngularJS application is to develop your initial "Hello World" program in the language. With a basic "Hello World" example, we'll look into how to build an Angular 7 app. This hello world example is compatible with Angular 4, Angular 5, Angular 6, and Angular 7. Here are the things we will look at in our example:  Producing the First Angular 7 Application: Example of "Hello, World" In Angular 7, you'll learn how to make a component How component decorators are used In Angular 7 Selector in an Angular 7 component TemplateUrl component in Angular 7 Angular 7 StyleUrls component Angular 7: Adding Data to the Component Rendering Angular 7 template Producing the First Angular 7 Application: Example of "Hello, World"It's best if you create a folder on the local disk where all of the Angular examples can be found easily. To navigate to the folder you have created, open a command prompt.  To create a new project in Angular from scratch, use the ng new command.ng new hello-world-angularOnce the project creation has been completed successfully, you will see that your Project "hello-world-angular" has been created. Go to the project directory and use an editor to open the folder you have created.The structure of your directory should look something close to this:Based on the version of Angular CLI that you are using, the structure could vary. Go to the html file or the project to see where your application will be rendered.  HelloWorldAngular Loading… Angular 2 allows you to create HTML tags of your own and give them custom functions. These will then be called 'components.' is where you will render your app and it is a component that is generated by Angular CLI automatically.  Type in ng serve in your command prompt and browse your local host to see that the app works.Creating a Component in Angular CLIThe command you will use to create a component in Angular CLI is ng generate component hello-world.As you can see from the image below, it will create four files.Open the “hello-world.component.ts” in your editor, for this written TypeScript component. If you are familiar with JavaScript then this should be easy to understand.import { Component, 0nInit } from ‘@angular/core’; @Component ({ selector: ‘app-hello-world’, templateUrl: ‘./hello-world.component.html’, styleUrls: [‘./hello-world.component.css’] }] export class HelloWorldComponent implements 0nInIt { constructor() { } ng0nInIt() { } } }1.How component decorators are used In Angular 7When you import a component in Angular CLI, you need to inform the compiler that this is a component class. Decorators are the elements used in Angular to do this. They can be described as the metadata that is added to a code. In our Hello World Example in the \hello-world-angular\src\app\app-module.ts file, according to the decorator, the class is named "AppModule". This is an NgModule.The App Module can also be called the root module. Every app must contain at least one module and that is the App Module. The @NgModule metadata plays an important role in guiding the Angular compilation process that converts the application code you write into highly performant JavaScript code.@Component ({ selector: ‘app-hello-world’, templateUrl: ‘./hello-world.component.html’, styleUrls: [‘./hello-world.component.css’] })Component contains three important declarations:2.Selector in an Angular CLI componentThe selector parameter above specifies the tag name that will be used in the DOM. (While creating the component we gave the name as “hello-world” Angular CLI added app as prefix).3.TemplateUrl component in Angular 7 tag uses hello-world.component.html file as html template. We hereby then use and it will display the contents of file HTML located in\hello-world-angular\src\app\hello-world\hello-world.component.html@Component ({ selector: ‘app-hello-world’, template:` hello-world works! `, styleUrls: [‘./hello-world.component.css’] }]Inline html templates are suitable for small html contents. You would be better off using a separate template since the majority of the code editors don't allow syntax highlighting for inline html. 4.Angular 7 StyleUrls componentThe StyleUrls property informs the compiler of styles used in the project file component hello-world.component.css.  Open \hello-world-angular\src\app\app.component.html file and add the created component as shown below.  and then refresh your browser.5.Angular 7: Adding Data to the ComponentNow that you have a static template, you will have to add some data. Open your file in the editor. The file that you are opening is the “hello-world.component.ts” file. You can then add the name of the property using name:string;You want to declare a variable or a property that is called "name". It is a string type. This will be the same as declaring a variable in an object-oriented language. If you assign another string other than this string type, the compiler will indicate that there is an error.  Assign the name variable on the constructor. It will then be called whenever you create a new class or a new instance.6.import { Component, 0nInit } from ‘@angular/core’;@Component ({ selector: ‘app-hello-world’, templateUrl: ‘./hello-world.component.html’, styleUrls: [‘./hello-world.component.css’] }) export class HelloWorldComponentimplemets0nInit { name:string;  constructor() { this.name=”AngularJs Wiki” } ng0nInit() { } }7.Rendering Angular 7 template.Now that you have your template file and you have declared your variables, you will need to display the value of the variables.  You can do this using two curly brackets that are called template tags. {{ }}Open hello-world.component.html which is your template file.  Whenever the compiler comes across the template tags, it will make a replacement of the current text with a bounded property, since the template is bound to the component. Refresh your browser once you have made this input. hello-world works! {{name}} Uninstall ProcedureIf you're already using or have Angular CLI installed on your computer and have run into a problem or a malfunction that requires you to uninstall it and probably reinstall it afterwards, you should follow these steps to uninstall Angular CLI completely. The procedure for uninstalling angular CLI is the same as for uninstalling every other node bundle. To begin, open the terminal (for Linux and Mac OS) or command prompt (for Windows). After you have done this, type the commands below line by line.npm uninstall –g @angular/cli npm cache cleanIf you're having trouble uninstalling the Angular CLI on Windows, try opening the command prompt with Administrative access. Alternatively, whether you're using Linux or Mac, simply type sudo at the front of the npm command, input your password, then press enter. Once you have done this, wait for the terminal operation to be complete.Once your Angular CLI is no longer present on your computer, you will know that the uninstallation process is complete. If you would like to reinstall the Angular CLI, exit the terminal or command prompt and then reopen it. Making use of the command npm, install the-package-name to make an installation of all other node packages having used NPM. It will be placed in the node_modules directory after that.  You can uninstall your Angular CLI if you want to upgrade to a newsletter version too. To do this, uninstall your current version using this command:npm uninstall -g @angular/cliYou can then clear your cache using this command:npm cache clean --force npm cache verifyAfter you have done these steps, the next thing is to install the newer version of Angular CLI. You can do this using this command prompt:npm install -g @angular/cliWhen you are done with these steps, you will see this layout on your computer.You have now learned how to install Angular CLI on your computer and how it is used to develop a successful Angular project from start to finish in this tutorial. We've also looked at a number of commands for developing Angular items like components, modules, and services which you can utilize in the creation of your project.  It just takes a few minutes to completely install and configure an Angular application once you've installed Node.js (npm) and Angular CLI onto your computer. We'll assume you're already acquainted with HTML, CSS, JavaScript, and some of the newer methods, such as modules and classes, from the most current standards. TypeScript is used to write the code samples. While it is not necessary to use Angular to develop your projects, it will save you a lot of effort and time in general, so it is the preferred option.
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How to Install Angular CLI

How to Install Angular CLIFor developing modern we... Read More

How to Install Node.JS on a Mac

Node.js is an opensource JavaScript platform for general-purpose programming that allows users to quickly build network applications. As it uses JavaScript on both the front and backend, development becomes far more consistent and integrated. Node.js runs on various platforms (Windows, Linux, Unix, Mac OS, etc.) In this tutorial, we will discuss about Node.js installation on macOS.As we have already mentioned, Node.js allows you to write JavaScript on the server-side. JavaScript, as you know, is a browser-based language. The creator of Node.js took the engine of Chrome and set it to work on a server. The browser's engine compiles JavaScript code into commands, and the language can be interpreted in an environment.  Npm is the platform for Node.js package management. It offers a tool for Node.js libraries to be installed, and their versions and dependencies managed.PrerequisitesHardware Requirement:RAM: 4 GB Storage: 256 GB of Hard Disk Space Software Requirements:Web Browser: Any browser such as Google Chrome, Mozilla Firefox, Microsoft Edge, Safari.XCode: XCode software is used by Apple in building Mac and iOS applications, so it provides the instruments you need to compile Mac software. You can find XCode in the Apple App Store.  Homebrew: Homebrew is a package manager for the Mac. It readily allows the installation of most open-source software (like Node).  On the Homebrew website, you can find out more about Homebrew.Operating System: macOSInstallation ProcedureIn this article, we are going to look at three different ways to install Node.js on macOS.using the macOS installer  using homebrew  using Node Version ManagerSo, let us start.1. Using the macOS installerStep 1: Visit the Node.js website to update your Mac platform with the built installer.Node.js updates comprise two types, long-term support (LTS) and new releases. LTS versions are refined and bug-free, and are sufficient for most daily users. Current versions (Latest LTS 14.16.1) are more experimental and include the new functionality, which cannot be completed or crashed from time to time. By highlighting the field on the first tab, you can move between LTS and current versions. Again, most users use the LTS version. Therefore, you can just click on macOS installer, which will download the Node.js installer, if the LTS tab is highlighted in dark green.Step 2: Download .pkg installer and open the downloaded file with default installer.Step 3: After running the .pkg installer, follow the instructions on the interface.1. Introduction window: select Continue2. Licence window: Select Continue and a pop-up window will ask you to agree or disagree. Click on Agree to proceed.3. Select Install and Authenticate your macOS password.4. You will see that Node.js and npm are installed on the interface.Step 4: Verify the installation of Node.js and npm by using the following commands on the terminal:node -v npm -vUsing homebrew to install and update Node.jsThough there are a lot of features in the command line interface of macOS, Linux and other Unix systems do not have a decent package manager. A Package Manager consists of a series of software tools that automatically install, configure and update the software.They manage the software in a central location and maintain all the device software packages in widely used formats. The Homebrew software package management framework is free and open-source and simplifies the installation of macOS software. The latest version of Node.js can be installed using Homebrew.Step 1: Use the following command to install Homebrew:s$ /usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"When CURL downloads the script, the Ruby-interpreter starts the Homebrew installation process, which ships with macOS.During the operation, you will be asked to enter your password. While you don't see them, the machine records your keystrokes, so once your password has been entered, click the RETURN key.Step 2: Once homebrew is installed, use the following command to install Node.js:$ brew update $ brew install nodeStep 3: Verify the installation and check the version of Node.js and npm.$ node -v $ npm -vHomebrew always installs only the latest version of Node.js. This may be problematic since a certain version of Node.js might be required to function in applications. It can be a good thing to have the freedom to use those versions. The easiest way to solve this problem is by using NVM, the Node Version Manager.Using nvm to install and update Node.jsNVM is a bash script for several active versions of Node.js. Follow these steps to install Node.js:Step 1: The script copies the nvm-repository to ~/.nvm and then attaches the sources to the profile of the shell: ~/.bash profile, ~/.zshrc and ~/.profile or ~/.bashrc. Depending on what you have on your machine you can use curlUse the following command:$ curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.35.3/install.sh | bashStep 2:  Add the source lines in your shell profile. You can use ~/.bash_profile, ~/.zshrc, ~/.profile, or ~/.bashrc. In this article, we will be using zsh shell:$ vim .zshrcStep 3: Paste the following lines of code:export NVM_DIR="$HOME/.nvm"[ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh" [ -s "$NVM_DIR/bash_completion" ] && \. "\$NVM_DIR/bash_completion"Close the file by using esc + w + qStep 4: Use the following command to reload the shell:$ source ~/.zshrcStep 5: You can verify the installation with the following command and if the screen shown had nvm written as the output, then the installation is successful.$ command -v nvmNote: You can check the various commands of nvm with the following command:$ nvm + tab keyStep 6: Install LTS version:$ nvm install –ltsStep 7: Install the latest version of node:$ nvm install nodeThis is an alias for the latest version.Step 8: You can list out all the installed Node.js versions available on your system:$ nvm listStep 9: Install NPM:$ nvm install-latest -npmStep 10: This installs the latest NPM. After you've set up NPM, you can try out a number of useful commands:List and update globally installed packages:$ npm ls -g  --depth=0 $ npm update  -gCreate a simple ProgramLet's create a simple program "Hello, world." This ensures that our environment works and that you can build and run a Node.js program conveniently.Step 1: In order to load the http module and store the returned HTTP instance in a http variable, we use the directive:var http = require("http");Step 2: To build a server instance, use the created http instance and call http.createServer() and connect it to port 8081 through the servers instance. Pass a function with request and response parameters. We will print Hello World!http.createServer(function (request, response) {    // Send the HTTP header      // HTTP Status: 200 : OK    // Content Type: text/plain    response.writeHead(200, {'Content-Type': 'text/plain'});    response.end('Hello World\n'); }).listen(8081); console.log('Server running at http://127.0.0.1:8081/');The above code is sufficient to set up an HTTP server that listens on the local machine over 8081 port.Step 3: Create a hello.js file using the following command:$ nano hello.jsStep 4: We will combine both the steps in a file hello.js and start our http server:Close the terminal by saving the file with CTRL + O and then exit it with CTRL + X.Step 5: Execute the hello.js to start the server with the following command:$ node hello.jsStep 6: Check the server at http://127.0.0.1:8081/Finally, we have our first http server up.Uninstall Node.js on macOSEarlier we have discussed the installation of Node.js on Mac with three different methods. Now, we will discuss the different ways to uninstall Node.js from your system:1. ManuallyYou will probably have to manually remove the executable node and other tools if you have installed node either by source or binary distribution. This is not simple, unfortunately, because several folders, such as npm and node modules, contain node resources.Use this official command to delete the node, node_modules folder:$ curl -ksO   https://gist.githubusercontent.com/nicerobot/2697848/raw/uninstall-node.sh $ chmod +x ./uninstall-node.sh $ ./uninstall-node.sh $ rm uninstall-node.sh2. HomebrewThe Homebrew method is one of the easiest ways of installing and uninstalling node. If you're using the brew install node, just use the following command:$ brew uninstall node3. Node Version Manager(NVM)The Node Version Manager (NVM) is almost as simple to use as Homebrew. You can install several node versions on your system to allow you to migrate easily from one version to the next.Finally, when you're done, you'll probably want to get rid of one of the versions. You can do this quickly:$ nvm uninstall For example:$ nvm uninstall v16.0.0.1ConclusionYou have installed Node.js, npm successfully and checked the setup using a simple program. You can now use it to build applications on the client or on the server.You have also seen how to install Node.js via homebrew, probably the most popular macOS package manager.However, Node Version Manager is the fastest way to install Node.js. This provides additional control and versatility in adopting various versions of Node.js, which may be needed if you switch between different projects based on your needs.
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How to Install Node.JS on a Mac

Node.js is an opensource JavaScript platform for g... Read More