Node.js tutorial in Visual Studio Code
Node.js is a platform for building fast and scalable server applications using JavaScript. Node.js is the runtime and npm is the Package Manager for Node.js modules.
Visual Studio Code has support for the JavaScript and TypeScript languages out-of-the-box as well as Node.js debugging. However, to run a Node.js application, you will need to install the Node.js runtime on your machine.
To get started in this walkthrough, install Node.js for your platform. The Node Package Manager is included in the Node.js distribution. You’ll need to open a new terminal (command prompt) for the node and npm command-line tools to be on your PATH.
To test that you have Node.js installed correctly on your computer, open a new terminal and type node —version and you should see the current Node.js version installed.
Linux: There are specific Node.js packages available for the various flavors of Linux. See Installing Node.js via package manager to find the Node.js package and installation instructions tailored to your version of Linux.
Windows Subsystem for Linux: If you are on Windows, WSL is a great way to do Node.js development. You can run Linux distributions on Windows and install Node.js into the Linux environment. When coupled with the WSL extension, you get full VS Code editing and debugging support while running in the context of WSL. To learn more, go to Developing in WSL or try the Working in WSL tutorial.
Hello World
Let’s get started by creating the simplest Node.js application, "Hello World".
Create an empty folder called "hello", navigate into and open VS Code:
Tip: You can open files or folders directly from the command line. The period ‘.’ refers to the current folder, therefore VS Code will start and open the Hello folder.
From the File Explorer toolbar, press the New File button:
and name the file app.js :
By using the .js file extension, VS Code interprets this file as JavaScript and will evaluate the contents with the JavaScript language service. Refer to the VS Code JavaScript language topic to learn more about JavaScript support.
Create a simple string variable in app.js and send the contents of the string to the console:
Note that when you typed console. IntelliSense on the console object was automatically presented to you.
Also notice that VS Code knows that msg is a string based on the initialization to ‘Hello World’ . If you type msg. you’ll see IntelliSense showing all of the string functions available on msg .
After experimenting with IntelliSense, revert any extra changes from the source code example above and save the file ( ⌘S (Windows, Linux Ctrl+S ) ).
Running Hello World
It’s simple to run app.js with Node.js. From a terminal, just type:
You should see "Hello World" output to the terminal and then Node.js returns.
Integrated Terminal
VS Code has an integrated terminal which you can use to run shell commands. You can run Node.js directly from there and avoid switching out of VS Code while running command-line tools.
View > Terminal ( ⌃` (Windows, Linux Ctrl+` ) with the backtick character) will open the integrated terminal and you can run node app.js there:
For this walkthrough, you can use either an external terminal or the VS Code integrated terminal for running the command-line tools.
Debugging Hello World
As mentioned in the introduction, VS Code ships with a debugger for Node.js applications. Let’s try debugging our simple Hello World application.
To set a breakpoint in app.js , put the editor cursor on the first line and press F9 or click in the editor left gutter next to the line numbers. A red circle will appear in the gutter.
To start debugging, select the Run and Debug view in the Activity Bar:
You can now click Debug toolbar green arrow or press F5 to launch and debug "Hello World". Your breakpoint will be hit and you can view and step through the simple application. Notice that VS Code displays a different colored Status Bar to indicate it is in Debug mode and the DEBUG CONSOLE is displayed.
Now that you’ve seen VS Code in action with "Hello World", the next section shows using VS Code with a full-stack Node.js web app.
Note: We’re done with the "Hello World" example so navigate out of that folder before you create an Express app. You can delete the "Hello" folder if you want as it is not required for the rest of the walkthrough.
An Express application
Express is a very popular application framework for building and running Node.js applications. You can scaffold (create) a new Express application using the Express Generator tool. The Express Generator is shipped as an npm module and installed by using the npm command-line tool npm .
Tip: To test that you’ve got npm correctly installed on your computer, type npm —help from a terminal and you should see the usage documentation.
Install the Express Generator by running the following from a terminal:
The -g switch installs the Express Generator globally on your machine so you can run it from anywhere.
We can now scaffold a new Express application called myExpressApp by running:
This creates a new folder called myExpressApp with the contents of your application. The —view pug parameters tell the generator to use the pug template engine.
To install all of the application’s dependencies (again shipped as npm modules), go to the new folder and execute npm install :
At this point, we should test that our application runs. The generated Express application has a package.json file which includes a start script to run node ./bin/www . This will start the Node.js application running.
From a terminal in the Express application folder, run:
The Node.js web server will start and you can browse to http://localhost:3000 to see the running application.
Great code editing
Close the browser and from a terminal in the myExpressApp folder, stop the Node.js server by pressing CTRL+C .
Now launch VS Code:
Note: If you’ve been using the VS Code integrated terminal to install the Express generator and scaffold the app, you can open the myExpressApp folder from your running VS Code instance with the File > Open Folder command.
The Node.js and Express documentation does a great job explaining how to build rich applications using the platform and framework. Visual Studio Code will make you more productive in developing these types of applications by providing great code editing and navigation experiences.
Open the file app.js and hover over the Node.js global object __dirname . Notice how VS Code understands that __dirname is a string. Even more interesting, you can get full IntelliSense against the Node.js framework. For example, you can require http and get full IntelliSense against the http class as you type in Visual Studio Code.
VS Code uses TypeScript type declaration (typings) files (for example node.d.ts ) to provide metadata to VS Code about the JavaScript based frameworks you are consuming in your application. Type declaration files are written in TypeScript so they can express the data types of parameters and functions, allowing VS Code to provide a rich IntelliSense experience. Thanks to a feature called Automatic Type Acquisition , you do not have to worry about downloading these type declaration files, VS Code will install them automatically for you.
You can also write code that references modules in other files. For example, in app.js we require the ./routes/index module, which exports an Express.Router class. If you bring up IntelliSense on index , you can see the shape of the Router class.
Debug your Express app
You will need to create a debugger configuration file launch.json for your Express application. Click on Run and Debug in the Activity Bar ( ⇧⌘D (Windows, Linux Ctrl+Shift+D ) ) and then select the create a launch.json file link to create a default launch.json file. Select the Node.js environment by ensuring that the type property in configurations is set to "node" . When the file is first created, VS Code will look in package.json for a start script and will use that value as the program (which in this case is "$
Save the new file and make sure Launch Program is selected in the configuration dropdown at the top of the Run and Debug view. Open app.js and set a breakpoint near the top of the file where the Express app object is created by clicking in the gutter to the left of the line number. Press F5 to start debugging the application. VS Code will start the server in a new terminal and hit the breakpoint we set. From there you can inspect variables, create watches, and step through your code.
Deploy your application
If you’d like to learn how to deploy your web application, check out the Deploying Applications to Azure tutorials where we show how to run your website in Azure.
Next steps
There is much more to explore with Visual Studio Code, please try the following topics:
How to run JavaScript in Visual Studio Code
In this short tutorial, you will learn how to run JavaScript in Visual Studio Code. There are three ways you can run JavaScript in the text editor and for that, feel free to choose whatever suits you the best.
Method 1: Use HTML script tag
The simplest way to run JavaScript in VS Code is to create an HTML file. This method is straightforward as you only need VS Code and a browser of your choice to view JavaScript outputs. Here’s how you will do it:
- Create an HTML file in VS Code and inside the file, add the script tags. You can write JavaScript code inside the script tags.
- Save the changes and then open the HTML file in the browser.
- In the browser, open the inspect window by right-clicking the mouse and select Inspect option. You can also open it by clicking Ctrl + Shift + I keys for Windows, or Cmd + Option + I keys for Mac.
- In the Inspect Window, click the Console tab, and this is where you can see the JavaScript outputs.
The only downside of using this approach is you will constantly switch between a browser and VS Code windows. Unless you’re working on smaller windows or have two monitor screens, this will inconvenience you a little bit.
Method 2: Use Node.js
Another way to run JavaScript in VS Code is using Node.js. This method will let you run JavaScript files directly on the text editor’s terminal, and no need to switch windows like in method 1. Here are the steps to run JavaScript with Node.js:
- Download and install Node.js on your computer.
- Open the JavaScript file that you want to run it.
- Open VS Code’s terminal by clicking Terminal >New Terminal, or clicking Ctrl + Shift + ` keys (Cmd + Shift+ P for Mac).
- In the terminal, type node file_name.js where file_name.js is the name of your JavaScript file. For example, if your file name is app.js, write node app.js click enter key to see the JavaScript output.
Method 3: Use Code Runner Extension
If you don’t like to run JavaScript manually, you can use the Code Runner Extension. While you don’t need to configure anything, you still have to install Node.js on your computer. To run JavaScript on Code Runner Extension:
- Click the Extensions tab, and search for Code Runner and install it.
- Open any JavaScript file and to run it, right-click the mouse and click the Run Code option or Ctrl + Alt + N. It will open the text editor’s Output window, and you can see the JavaScript outputs.
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Node.js tutorial in Visual Studio Code
Node.js is a platform for building fast and scalable server applications using JavaScript. Node.js is the runtime and npm is the Package Manager for Node.js modules.
Visual Studio Code has support for the JavaScript and TypeScript languages out-of-the-box as well as Node.js debugging. However, to run a Node.js application, you will need to install the Node.js runtime on your machine.
To get started in this walkthrough, install Node.js for your platform. The Node Package Manager is included in the Node.js distribution. You’ll need to open a new terminal (command prompt) for the node and npm command-line tools to be on your PATH.
To test that you have Node.js installed correctly on your computer, open a new terminal and type node —version and you should see the current Node.js version installed.
Linux: There are specific Node.js packages available for the various flavors of Linux. See Installing Node.js via package manager to find the Node.js package and installation instructions tailored to your version of Linux.
Windows Subsystem for Linux: If you are on Windows, WSL is a great way to do Node.js development. You can run Linux distributions on Windows and install Node.js into the Linux environment. When coupled with the WSL extension, you get full VS Code editing and debugging support while running in the context of WSL. To learn more, go to Developing in WSL or try the Working in WSL tutorial.
Let’s get started by creating the simplest Node.js application, «Hello World».
Create an empty folder called «hello», navigate into and open VS Code:
Tip: You can open files or folders directly from the command line. The period ‘.’ refers to the current folder, therefore VS Code will start and open the Hello folder.
From the File Explorer toolbar, press the New File button:
and name the file app.js :
By using the .js file extension, VS Code interprets this file as JavaScript and will evaluate the contents with the JavaScript language service. Refer to the VS Code JavaScript language topic to learn more about JavaScript support.
Create a simple string variable in app.js and send the contents of the string to the console:
Note that when you typed console. IntelliSense on the console object was automatically presented to you.
Also notice that VS Code knows that msg is a string based on the initialization to ‘Hello World’ . If you type msg. you’ll see IntelliSense showing all of the string functions available on msg .
After experimenting with IntelliSense, revert any extra changes from the source code example above and save the file ( kb(workbench.action.files.save) ).
Running Hello World
It’s simple to run app.js with Node.js. From a terminal, just type:
You should see «Hello World» output to the terminal and then Node.js returns.
VS Code has an integrated terminal which you can use to run shell commands. You can run Node.js directly from there and avoid switching out of VS Code while running command-line tools.
View > Terminal ( kb(workbench.action.terminal.toggleTerminal) with the backtick character) will open the integrated terminal and you can run node app.js there:
For this walkthrough, you can use either an external terminal or the VS Code integrated terminal for running the command-line tools.
Debugging Hello World
As mentioned in the introduction, VS Code ships with a debugger for Node.js applications. Let’s try debugging our simple Hello World application.
To set a breakpoint in app.js , put the editor cursor on the first line and press kb(editor.debug.action.toggleBreakpoint) or click in the editor left gutter next to the line numbers. A red circle will appear in the gutter.
To start debugging, select the Run and Debug view in the Activity Bar:
You can now click Debug toolbar green arrow or press kb(workbench.action.debug.start) to launch and debug «Hello World». Your breakpoint will be hit and you can view and step through the simple application. Notice that VS Code displays a different colored Status Bar to indicate it is in Debug mode and the DEBUG CONSOLE is displayed.
Now that you’ve seen VS Code in action with «Hello World», the next section shows using VS Code with a full-stack Node.js web app.
Note: We’re done with the «Hello World» example so navigate out of that folder before you create an Express app. You can delete the «Hello» folder if you want as it is not required for the rest of the walkthrough.
An Express application
Express is a very popular application framework for building and running Node.js applications. You can scaffold (create) a new Express application using the Express Generator tool. The Express Generator is shipped as an npm module and installed by using the npm command-line tool npm .
Tip: To test that you’ve got npm correctly installed on your computer, type npm —help from a terminal and you should see the usage documentation.
Install the Express Generator by running the following from a terminal:
The -g switch installs the Express Generator globally on your machine so you can run it from anywhere.
We can now scaffold a new Express application called myExpressApp by running:
This creates a new folder called myExpressApp with the contents of your application. The —view pug parameters tell the generator to use the pug template engine.
To install all of the application’s dependencies (again shipped as npm modules), go to the new folder and execute npm install :
At this point, we should test that our application runs. The generated Express application has a package.json file which includes a start script to run node ./bin/www . This will start the Node.js application running.
From a terminal in the Express application folder, run:
The Node.js web server will start and you can browse to http://localhost:3000 to see the running application.
Great code editing
Close the browser and from a terminal in the myExpressApp folder, stop the Node.js server by pressing kbstyle(CTRL+C) .
Now launch VS Code:
Note: If you’ve been using the VS Code integrated terminal to install the Express generator and scaffold the app, you can open the myExpressApp folder from your running VS Code instance with the File > Open Folder command.
The Node.js and Express documentation does a great job explaining how to build rich applications using the platform and framework. Visual Studio Code will make you more productive in developing these types of applications by providing great code editing and navigation experiences.
Open the file app.js and hover over the Node.js global object __dirname . Notice how VS Code understands that __dirname is a string. Even more interesting, you can get full IntelliSense against the Node.js framework. For example, you can require http and get full IntelliSense against the http class as you type in Visual Studio Code.
VS Code uses TypeScript type declaration (typings) files (for example node.d.ts ) to provide metadata to VS Code about the JavaScript based frameworks you are consuming in your application. Type declaration files are written in TypeScript so they can express the data types of parameters and functions, allowing VS Code to provide a rich IntelliSense experience. Thanks to a feature called Automatic Type Acquisition , you do not have to worry about downloading these type declaration files, VS Code will install them automatically for you.
You can also write code that references modules in other files. For example, in app.js we require the ./routes/index module, which exports an Express.Router class. If you bring up IntelliSense on index , you can see the shape of the Router class.
Debug your Express app
You will need to create a debugger configuration file launch.json for your Express application. Click on Run and Debug in the Activity Bar ( kb(workbench.view.debug) ) and then select the create a launch.json file link to create a default launch.json file. Select the Node.js environment by ensuring that the type property in configurations is set to «node» . When the file is first created, VS Code will look in package.json for a start script and will use that value as the program (which in this case is «$
Save the new file and make sure Launch Program is selected in the configuration dropdown at the top of the Run and Debug view. Open app.js and set a breakpoint near the top of the file where the Express app object is created by clicking in the gutter to the left of the line number. Press kb(workbench.action.debug.start) to start debugging the application. VS Code will start the server in a new terminal and hit the breakpoint we set. From there you can inspect variables, create watches, and step through your code.
Deploy your application
If you’d like to learn how to deploy your web application, check out the Deploying Applications to Azure tutorials where we show how to run your website in Azure.
There is much more to explore with Visual Studio Code, please try the following topics:
How to run JavaScript in Visual Studio Code
This article conveys the execution of JavaScript in VSCode. The steps to run JavaScript inside Visual Studio are as follows:
1. The first step is the installation of Node.js on your MacBook/Windows in order to call scripts through Node.js. You can easily download Node.js by visiting https://nodejs.org/en/
2. In the second step you have to create a new folder then open this folder in Visual Studio Code. Subsequently, write JavaScript code and save it with an extension of “.js”.
3. Open up the operating system’s terminal inside Visual Studio Code by clicking on View on the topmost bar.
Example
To run a script named index.js in Visual Studio Code then you should first make sure that node.js is installed. Open the terminal within Visual Studio Code. You can now easily run JavaScript in the terminal of VSCode by using node.js. The syntax of the node command used to run JavaScript code is shown in the VSCode terminal.
In this example, we wrote the script to check if the number is even or odd. Subsequently, we execute the command in the terminal as shown below to get the output. In this case, we assigned 6 to the num variable and it gives the following output.
// this script used to check if the number is even or odd
const result = ( num % 2 != 0 ) ? "odd" : "even" ;
// display the result
console. log ( ` Number is $ { result } .` ) ;
Output
On the other hand, we assigned 43 to the num variable and it gives the following output.
// this script used to check if the number is even or odd
const result = ( num % 2 != 0 ) ? "odd" : "even" ;
// display the result
console. log ( ` Number is $ { result } .` ) ;
Output
An alternative way to run JavaScript in VSCode using Code Runner Extension
This is the simplest method to run JavaScript. There are no configurations required in this method. You need to install Node.js either way on your machines as the code runner extension also needs Node.js. Following steps must be kept in mind to run JavaScript in VSCode using a code runner extension.
1. First of all, you need to install Code Runner Extension in order to run JavaScript code. This extension will consume a couple of minutes to install and it is really easy to install it. You can easily download the code runner extension by visiting https://marketplace.visualstudio.com/items?itemName=formulahendry.code-runner
Then click on the Open URL:vscode button. The following window is shown as mentioned below.
2. After installation of the code runner extension, open JavaScript Code in VSCode. Press CTRL+ALT+N shortcut or you may press F1 then write Run Code to run the code. Subsequently, you will see the following output in the “OUTPUT” tab.
// this script used to check if the number is even or odd
const result = ( num % 2 != 0 ) ? "odd" : "even" ;
// display the result
console. log ( ` Number is $ { result } .` ) ;
Output:
Conclusion
Visual Studio gives quality, flexibility and also gives outstanding debugging experience to web applications using JavaScript. So, in order to run/execute JavaScript in Visual Studio Code we need NodeJS which acts as an interpreter. In this article, we demonstrate how to run JavaScript in Visual Studio Code and also explain an alternative way to run JavaScript in VSCode using Code Runner Extension along with detailed examples.