Node.js Tutorial in VS 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.

VS 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.

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.

Tip: To test that you've got Node.js correctly installed on your computer, open a new terminal and type node --help and you should see the usage documentation.

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:

mkdir hello
cd hello
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 tool bar, press the New File button:

File Explorer New File

and name the file app.js:

File Explorer 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.

Create a simple string variable in app.js and send the contents of the string to the console:

var msg = 'Hello World';
console.log(msg);

Note that when you typed console. IntelliSense on the console object was automatically presented to you. When editing JavaScript files, VS Code will automatically provide you with IntelliSense for the DOM.

console IntelliSense

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.

string IntelliSense

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:

node app.js

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 > Integrated Terminal (⌃` (Windows, Linux Ctrl+`) with the backtick character) will open the integrated terminal and you can run node app.js there:

integrated terminal

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 simply click in the editor left gutter next to the line numbers. A red circle will appear in the gutter.

app.js breakpoint set

To start debugging, select the Debug View in the Side Bar:

Debug icon

You can now click Debug tool bar 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 an orange Status Bar to indicate it is in Debug mode and the DEBUG CONSOLE is displayed.

hello world debugging

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 wish as it is not required for the rest of the walkthrough.

Express Tutorial

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:

npm install -g express-generator

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:

express myExpressApp

This creates a new folder called myExpressApp with the contents of your application. To install all of the application's dependencies (again shipped as NPM modules), go to the new folder and execute npm install:

cd myExpressApp
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:

npm start

The Node.js web server will start and you can browse to http://localhost:3000 to see the running application.

Your first Node Express App

Great Code Editing Experiences

Close the browser and from a terminal in the myExpressApp folder, stop the Node.js server by pressing CTRL+C.

Now launch VS Code:

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 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 what __dirname is. 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.

http IntelliSense

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 Typing 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 routes, you can see the shape of the Router class.

Express.Router IntelliSense

Debugging your Express Application

You will need to create a debugger configuration file launch.json for your Express application. Click on the Debug icon in the Activity Bar and then the Configure gear icon at the top of the Debug view to create a default launch.json file. Select the Node.js environment. 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 ${workspaceRoot}/bin/www) for the Launch Program configuration. A second Attach to Process configuration is also created to show you how to attach to a running Node.js application.

{
    "version": "0.2.0",
    "configurations": [
        {
            "type": "node",
            "request": "launch",
            "name": "Launch Program",
            "program": "${workspaceRoot}/bin/www",
            "cwd": "${workspaceRoot}"
        },
        {
            "type": "node",
            "request": "attach",
            "name": "Attach to Process",
            "port": 5858
        }
    ]
}

Save the new file and make sure Launch Program is selected in the configuration dropdown at the top of the 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.

Debug session

Deploying your Application to the Cloud

Let's finish up this walkthrough by deploying our application to the cloud. While it is possible to deploy directly to a web site, it is not a best practice. Instead, we will set up continuous deployment from a GitHub repository to an Azure App Service website (Azure's Platform as a Service offering). With this setup, you can use version control to roll back changes, configure different branches to deploy to different development "slots" (e.g. development or production) and more.

If this sounds complicated, don't worry, it isn't :).

If you don't have an Azure subscription, sign up today for a free 30 day account with $200 in Azure Credits to try out any combination of Azure services.

The first thing we'll need to do is get our source code into a GitHub repository. Browse to your GitHub account and create a new public repository.

Create a new GitHub repository


We are going to follow the instructions provided by GitHub to create a new repository on the command line, but with a few changes. It is a good practice to include a .gitignore file in your repository that excludes the node_modules folder. We'll do this instead of creating a README.md file and we'll add and commit all of the files in the workspace (except node_modules of course):

echo "node_modules" >> .gitignore
git init
git add .
git commit -m "first commit"
git remote add origin https://github.com/**YourGitHubAccount**/myExpressApp.git
git push -u origin master

Next, we will create an Azure Website to host our app. Once we have that, we'll configure the site to pull and deploy from the Git repository every time we push changes. To create the site, we'll use the new, cross platform Azure CLI.

Install the Azure CLI

The following CLI commands will create our site and set up continuous deployment. Make sure you name your site properly per the comments.

# Follow the login instructions
az login

# Create an Azure Resource Group which is essentially a container for all of your application resources.
az group create -l westus -n myExpressAppGroup

# Create an Azure App Service Plan which is essentially the machine on which your application will be hosted.
# In this walkthrough, we will use a FREE plan which will host your app on a machine with other websites.
az appservice plan create -n myExpressAppPlan -g myExpressAppGroup -l westus --sku FREE

# Now create the website and give it a unique name as it will be referenced as http://**myUniqueName-ExpressApp**.azurewebsites.net
az appservice web create -n myUniqueName-ExpressApp -g myExpressAppGroup -p myExpressAppPlan

# Let's test that our site is up and running. It will be a temporary site as we have not deployed any code here yet.
az appservice web browse -n myUniqueName-ExpressApp -g myExpressAppGroup

# Configure the site for continuous deployment through our GitHub repository.
az appservice web source-control config --repo-url https://github.com/yourgithubaccount/myExpressApp -n myUniqueName-ExpressApp -g myExpressAppGroup

Refresh the site and you should see your Express application hosted in the cloud on Azure!

Express app running in Azure


To test continuous deployment, make a change to the index.jade file found in the views folder and make a local commit.

Commit a change

Use the overflow menu to Sync the change with the GitHub repository.

Sync the change

Finally, the site will recognize a change has been pushed and the content will automatically be redeployed.

VS Code Rocks


Next Steps

There is much more to explore with Visual Studio Code, please try the following topics:

  • Settings - Learn how to customize VS Code for how you like to work.
  • Debugging - This is where VS Code really shines
  • Basic Editing - Learn about the powerful VS Code editor.
  • Code Navigation - Move quickly through your source code.
  • Tasks - Running tasks with Gulp, Grunt and Jake. Showing Errors and Warnings