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So you’re working on a Node.js application and getting awfully tired of restarting the process every time you make a change? Enter nodemon, a CLI utility developed by @rem that wraps your Node app, watches the file system for changes and automatically restarts the process.
Getting started with nodemon is as simple as it gets. Install the utility either globally or locally to your project using npm or Yarn:
Global installLocal install
As you can see, when doing a local install, we can install as a dev dependency. Note also that with a local install you won’t be able to use the nodemon command directly from the command line, but instead you can use it as part of some npm scripts, or with npx.
Basic Usage
Initiate the Node.js File. The file you have just created must be initiated by Node.js before any action can take place. Start your command line interface, write node myfirst.js and hit enter. Quickstart: Use Visual Studio to create your first Node.js app.; 3 minutes to read +2; In this article. In this 5-10 minute introduction to the Visual Studio integrated development environment (IDE), you'll create a simple Node.js web application.
The dockerfile defined in this example takes the following steps: Start FROM the pre-existing node:current-slim image. This is an official image, built by the node.js vendors and validated by Docker to be a high-quality image containing the Node.js Long Term Support (LTS) interpreter and basic dependencies.; Use WORKDIR to specify that all subsequent actions should be taken from the. Jul 21, 2017 Once it's done, you can test to see both node and npm functioning by opening PowerShell (or any shell) and typing node -v and npm -v, which will check the version number. Installation on a Mac or Linux. In order to install everything on a Mac, we'll be running commands in Terminal.app, and Linux distributions vary. Install Node.js and npm. How to Run a Node.js Application on a Mac. Node.js makes it possible for you to run JavaScript programs outside of a web browser or on a server. To run a Node.js application on MacOS, follow these three steps. Open Terminal by pressing Command+Space to open Spotlight Search and entering terminal into the search box.
It’s just as easy to use nodemon as it is to start a Node script. In fact, the same exact arguments can be passed-in to nodemon. For example, if we have a simple Express server setup in a
server.js file, we can start it and watch for changes like this:
Arguments can be passed-in the same way as if you were running the script with Node:
Now every time a change is made to a file with one of the default watched extensions (.js, .mjs, .json, .coffee or .litcoffee) in the current directory or a subdirectory, the process will restart:
Don't worry, the node_modules folder is ignored by default.
As you can see from the screenshot above, the terminal output from your Node.js app is displayed normally. You can restart the process at any time by typing rs and hitting enter.
Alternatively, nodemon will also look for a main file specified in your project’s
package.json file or a start script. Given either of the examples below, you can then simply call $ nodemon to start your app in watch mode:
Main file
package.json
Start script
package.json
Advanced Options
There are a bunch of options available, and you can access a summary of the available options with
$ nodemon -h .
Let’s go over a few of the main options:
Below, for example, we’re watching the server directory for files with a .ts extension, ignoring files with a .test.ts suffix, executing the file (
server/server.ts ) with ts-node and waiting for 3 seconds to restart after a file changes:
Config
As you saw from the above example, adding configuration switches when running nodemon can get quite tedious. A better solution for projects that need specific configurations is to specify these configs in a
nodemon.json file. For example, below are the same configurations as the above example, but placed in a nodemon config file:
nodemon.json
Note the use of execMap instead of the
--exec switch. execMap allows to specify binaries that should be used given certain file extensions.
With this, you can simply start nodemon with the desired script:
Alternatively, if you’d rather not add a
nodemon.json config file to your project, you can add these configurations to the package.json file under a nodemonConfig key:
package.json
latest workflow postsTaking a Look at the GitHub CLI ToolLinting on Save with Visual Studio Code and ESLintDeploying a Docker Application with AWSIntroduction to Kubernetesall workflow postsHello World with a Node.js Server![]()
Did you know that there are multiple ways to start a Node.js server and keep it running? In this post, we will explore various ways to start an HTTP Node server.
A Node.js server makes your app available to serve HTTP requests. It provides the interaction between users and your application.
Creating and starting a server is easy with Node.js's built-in
http module.
In a file app.js, create and save the following server-creation code:
In your terminal, run the command:
and visit
http://localhost:3000 in your browser.
You should see that our server is running, and you are greeted with the text 'Hello, World!' in your browser. We created an instance of an HTTP server using the built-in
http module. This is a simple but highly powerful server that can handle requests, issue responses and a whole lot more.
We can see the additional power of the basic HTTP server by extending it as follows to stream a video file. First, in the same directory with your
app.js file, create a new directory named assets. Inside assets, place an mp4 video file of your choice. Then adjust the new code listing below to replace my video name with your exact video name.
Now, when you restart the server and visit the app in the browser, you will see that our server is now streaming a video file.
Other Options for Starting a Server with Node.jsUsing Other Server Modules
We can also start a Node server using the server npm module. Note that this module requires Node version 7.6.0 or later.
In a fresh project, install the module with the command
npm install server --save . Then create a file app.js with the following contents:
Run the server with
In your browser, you should see the 'Hello world!' text.
If all you want is a Node.js server to serve HTML and serve static files without you coding anything for the server, Node has a solution for that as well. In this case you need to install the http-server zero-configuration, command-line server to serve your files.
To use
http-server , install it with the command npm install http-server -g .
In a fresh directory, create a child directory named public in which we will place static files for
http-server to serve. Create a static HTML file inside this public directory named index.html with the following contents:
Then you can run the
http-server using the command:
Visit http://localhost:8081 to verify that the server is running and serves our file with the 'Hello World' message. This Node.js serving option is useful for serving a simple app that does mainly front-end work.
Keeping Servers Running with forever
Another scenario arises when you have a running Node.js server that you want to keep running automatically. forever will help you keep Node servers running even after the operating system is rebooted. It also restarts your app after a crash, making it useful for monitoring and restarting Node servers.
Keep Servers Running with PM2
PM2 is an alternative to forever that keeps apps running between server restarts. It also has a built-in load balancer for improved uptime. It is a bit more powerful, but also complicated, so it may not be suited for beginners.
How Frameworks Help to Start a Node Server
Besides the options for running servers we discussed above, you can also run a server using code provided by the framework itself. Frameworks bring advantages like good default conventions and the ability to develop fast without writing common software routines from scratch.
A list of the most popular Node frameworks based on GitHub stars includes the following:
In the following sections we will show how to start a Node server using a few of these popular options.
Framework 1: Starting a Node Server with Express
Express is the most well-known minimalist web framework for Node.js. It is suited for all kinds of apps from small to large. Because it leaves most of the choices to the developer, it's good for seasoned developers.
To get started, create a new project folder with a file inside it named app.js.
Next, install Express with the following:
Now update app.js as follows to start a Node server using Express.
Run the server with the command:
and visit
http://localhost:3000 to see the Express server in action.
Framework 2: Starting a Node Server with Koa.js
Koa is a minimalist framework by the makers of Express. It aims to be simpler, even less opinionated, and more expressive. As such, it is recommended for developers who want a more purist approach than even Express provides.
Install Koa with:
Create the following minimal Koa app inside a new file, app.js.
Run this server by executing:
Then visit http://localhost:3000 in your browser to see the server running. You will be greeted by the same response text as we saw when running the Express server.
Framework 3: Node a Server with Socket.io
Socket.io is a real-time Node framework. It is particularly advantageous when you are developing messaging and chat applications. The platform works equally well for other apps involving bidirectional, event-based calls.
Create a new project and install Socket.io with the command:
Also install Express, which we'll use to integrate with Socket.io, using the command:
Then create a file index.js with the following:
What this does is create a socket.io instance attached to our Express server. When clients connect to the socket, our socket.io server sends back a 'Hello, World' greeting over the socket connection. To see the results, run the following command:
Framework 4: Server with Diet.js
Diet.js is a micro-framework for writing modular Node.js apps and APIs. It allows creating of virtual hosts and other cool features. You will want to consider it as an alternative to minimalist frameworks like Express. The core of the framework is only 450 SLOC. It integrates with a wide variety of middleware that runs on Node.js.
To start a server using Diet.js, create a new project and install Diet.js with:
Then, create a source file
index.js with the following code:
Start the server with the command:
And then visit http://localhost:3000 to view the server running.
Diet.js has a simple API, combining many concepts from Express in a simpler API and implementation. This reduces the learning curve for developing a simple app. If you have a bigger app in mind, more structured frameworks like Sails.js might suit you better.
Framework 5: Starting a Node Server with Sails.js
Sails is the Node.js answer to full-featured MVC frameworks like Ruby on Rails. Its use of Node.js real-time capabilities makes it a fit for apps using websockets and messaging. It comes with blueprints that make it easy to quickly prototype a backend with very little code.
Let's create a fresh new directory and install Sails with the following:
This installs Sails globally on your system. Then, create a Sails app with the command
$ sails new helloapp . Inside the newly created helloapp folder, run the Sails server with the command:
Visit http://localhost:1337 to see the app served locally.
Create Node App
Sails generated a complete app with the
sails new command. The app is initialized in the file app.js, which has the following generated contents:
The initialization code imports Sails, then loads the application and starts the Sails server.
Sails has the advantage of being particularly fast and scalable. In this benchmark against Rails, Sails performed as much as 3x-4x as fast. The performance-critical part of Sails for apps at scale tends to be the database, where pagination and indexes can be used to speed things up.
Framework 6: Using MEAN.io for a Node Server
MEAN.io is one of the more well-known full-stack JavaScript frameworks. It is one variant of the so-called 'MEAN Stack', with MEAN.js being another variant. MEAN uses MongoDB, Express, Angular and Node.js.
To start a MEAN.io app, clone the reference implementation of the MEAN.io model app using the command:
Suggested Course: Master the MEAN Stack - Learn By Example
You can alternatively clone into another directory of your choice. Then change into the new mean directory or your chosen directory, and install dependencies with:
Run the application with
npm start and visit http://localhost:4040 to see it in action.
The code for setting up the server is found in the file
serverconfigexpress.js which contains the following:
At the heart of the MEAN stack is an Express server that uses Node middleware such as bodyParser for processing request payloads, winston for request logging and helmet for securing HTTP requests.
The advantages of MEAN include being based on robust technologies that have proven ability to power high traffic apps. The reference app integrates MongoDB as well as Angular and React. It uses Typescript as well, along with some example components so that you can use them as a launching point. If you don't need a certain library, you can drop it from the dependencies in the package.json file.
Framework 7: Start a Node Server with LoopBack, the API Framework
Loopback is a Node framework that lets you build API-focused apps fast. It has automated parts of the API-creation process, making it possible to generate RESTful APIs with little to no coding. Loopback combines a set of modules that you can integrate as your app requirements grow. This lets you build apps in a modular way using standard Loopback modules.
Start Node App On Mac Windows 10
You can install Loopback globally with the command:
To create a project, run
lb , which will walk you through the creation of a basic Loopback application.
Pick the
hello-world app, to include a simple message and controller. The other options are to create an API, or a project containing a basic working example with a memory database.
Going with the
hello-world app type generates a basic app. Inside the file 'server/server.js' you will find the following generated code:
Start Node App On Mac Laptop
This code initializes the Loopback server, which you can start with the command
node . Visit http://localhost:3000 to verify the server is running. You can also look at http://localhost:3000/explorer to view the Loopback API interface.
Our API is empty to begin with. Creating a new model and REST endpoints is easy with the Loopback CLI. Run the command
lb model and type a model name such as 'movie', but without the quotes.
Then adjust the values for persistence and other setup according to the prompt or accept the defaults.
Create some properties of the model and define the data types. For example, a movie can have a title which will be a string. Enter as many properties as you'd like, and then finish.
Now we have an API for movies, which you can access with a GET request to http://localhost:3000/api/movies. This will return an empty JSON array. You can explore the API with the API explorer at http://localhost:3000/explorer.
Create some movies and then interact with the API in the browser to see the Loopback server in action. Also, look at the generated source code for the API. Loopback makes developing APIs really easy.
Choosing the Best Node Server for your App
Choosing the best way for serving your Node.js application involves a series of trade-offs. Rolling your own framework based on the
http module is practical, given the wide range of middle-ware you can integrate with a Node app. This path gives you the ability to make all the choices yourself about how your app will work.
Going with a framework such as Socket.io or Sails lets you build on a tested foundation that others have used successfully. The wide range of frameworks also makes it possible for you to reuse code from these libraries to get started a bit faster.
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The trade-off with frameworks, particularly opinionated ones like Sails, is that some of the technical choices are already made for you. Best free archive software machine. If you want something outside the norm of what the framework is optimized for, you could have a hard time. Koa and Express offer a safe middle ground where very few choices or assumptions about your app have been made.
Here is a quick guide to selecting the framework that lets you build effectively depending on your app's needs:
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