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#Nodejs commander how to
#Nodejs commander install
#Nodejs commander full
#Nodejs commander software
#Nodejs commander code

In this post we'll look at why you might want to write a CLI, how to use Node.js for it, some useful packages and how you can distribute your new CLI. And thanks to package managers like npm and yarn, these can be easily distributed and consumed across multiple platforms.

#Nodejs commander install

Here we discuss the introduction and how to install node.js along with its working including the commands and examples.Command-line interfaces (CLIs) built in Node.js allow you to automate repetitive tasks while leveraging the vast Node.js ecosystem. We also walked through the working of Node.js, i.e the communication between client and server, how Node.js handles a request asynchronously (in a non-blocking way), and acknowledged the role played by Event Loop and Internal Thread Pool in the execution of requests and sending back responses to the client. Thus, we learned how to create a Node.js project through command prompt, also the importance of package.json file required fields in package.json file and created our very first web server using HyperText Transfer Protocol module. The above scenario explains how Node.js handles concurrent client requests and operates on a single thread and does not need the creation of multiple threads. It uses fewer threads so that it can use fewer resources. Node.js is used to build highly scalable, data-intensive applications. It operates in a non-blocking way and is event-driven. When the next request arrives, it again checks if that current request requires to query the database, if not then the thread takes the request ahead, processes it, and sends back the response to the client. The event loop, in turn, sends the response back to the client.ġ0. A thread is then assigned to look after the request, which takes the request forward, processes it, prepares the response, and sends it back to the Event Loop.ĩ. Internal Thread Pool consists of multiple threads.Ĩ. It then checks the thread availability in Internal Thread Pool. When a request is placed in the Event Queue, it starts processing that particular client request.ħ. Event Queue operates on a single thread only.Ħ. Meanwhile, for the first request which involves interaction with the database, the thread places that particular request in the Event Queue.ĥ. The thread then checks if the request requires querying the database or any complex operations, the thread does not wait for the database to return the value, instead, the thread is ready to serve another request.Ĥ. The client sends a request to the server.ģ. In Node.js, a single thread handles the incoming requests.Ģ. How Node.js Works?Īs we are aware, Node.js works asynchronously (non-blocking) let us understand the working process:ġ. Thus, the above image depicts the creation of our first web server that listens to port 5000. Step 6: After running the app.js file, you can check the output by switching into Google chrome browser and type: you will find the following output:

#Nodejs commander code

Step 5: To execute the code snippet, use the following command as shown in the picture below:

The type of response headers is depicted through the “res.setHeader(‘Content-type’, ’text-plain’)”.

When the response contains the statuscode “200”, it depicts that the request is processed properly and received an appropriate response.

The arguments passed for the function createserver() are req and res representing request and response.

What does listen() does – It listens to the server port mentioned in the code, in the above example, it listens to the port 5000.

What is the use of createserver() – createserver() is a method of HTTP module that creates a server.

What does the require() do – Require() is used to include the HTTP module.

Why HTTP – HTTP module gives the privilege to create a web server that listens to server ports and sends a response back to the client.

What is HTTP – HTTP module stands for HyperText Transfer Protocol which allows Node.js to transfer the information.

Let us understand what the code is all about: webpages) to the client.Ĭreate an app.js file in your root directory.Ĭopy and paste the following code snippet. browsers) and sends back a response (e.g.

#Nodejs commander software

Step 4: Let us now learn how to create a web serverĪ web server is a software application that handles the HTTP requests sent by HTTP clients (e.g. It represents all the information regarding the project and the packages with its version. The “package.json” is an essential file that is present in the root directory of the project. The two required fields in a “package.json” file are “name” and “version”. A “package.json” file lists all the packages that your project depends on.

#Nodejs commander full

The full form for JSON is JavaScript Object Notation. Once the project is initialized upon using the command “npm init”, a “package.json” the file is created.

The above three steps can be seen in the below screenshots: Step 3: To initialize the project, use the command