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Introduction to Express.js

Express.js is a popular web framework for Node.js, a JavaScript runtime that allows developers to build server-side applications. Node.js was developed by Ryan Dahl in 2009 and is designed to enable efficient, scalable, and high-performance server-side applications using JavaScript. Express.js was created in 2010 by TJ Holowaychuk as a minimalist and flexible web application framework for Node.js.

Express.js provides a range of features that make it easy to build web applications, including routing, middleware, and templating engines. It also integrates seamlessly with databases, making it easy to store and retrieve data in a web application.

One of the key advantages of Express.js is its flexibility. Developers can use it to build web applications in a variety of styles, including traditional server-side rendered applications, single-page applications (SPAs), and RESTful APIs. Express.js can also be used in conjunction with other tools and frameworks, such as React and Angular, to build more complex and feature-rich applications.

Node.js and Express.js have become very popular among developers, particularly for building scalable and efficient server-side applications. They are used by companies such as Netflix, PayPal, and LinkedIn, and have a large and active community of developers who contribute to their ongoing development and support.

Check Node version​

To check the Node.js version installed on your machine, you can use the following command in your terminal or command prompt:

node -v

Check npm version​

npm stands for Node Package Manager. It is a package manager for the JavaScript programming language and is used to manage the dependencies (third-party libraries and modules) of Node.js-based projects.

When you develop a Node.js application, you often need to use external libraries and modules to implement specific functionality. npm provides an easy way to install and manage these dependencies, allowing you to easily include them in your project and manage their versions.

npm is included with Node.js and is automatically installed on your system when you install Node.js. npm provides a command-line interface (CLI) that you can use to install, manage, and publish packages. You can also use it to search for packages in the npm registry, which is a public repository of open-source packages.

npm is widely used by Node.js developers and has become a critical tool in the Node.js ecosystem. It makes it easy to share and reuse code, and helps to ensure that Node.js projects are built using secure, up-to-date, and well-documented dependencies.

If you want to check the version of npm (Node Package Manager) installed on your machine, you can use the following command:

npm -v

Create package.json​

To create a package.json file for your Node.js project, you can use the following steps:

  • Open your terminal or command prompt.
  • Navigate to the root directory of your project using the cd command.
  • Run the following command:
npm init
  • Follow the prompts to enter information about your project, such as its name, version, description, entry point, and author. You can also leave some fields blank or use the default values by pressing Enter key.
  • Once you've entered all the necessary information, a package.json file will be generated in your project's root directory.
Note

If you want to skip the prompts and create a package.json file with default values, you can use the following command:

npm init -y

This will generate a package.json file with default values, without any prompts. You can then edit the file manually to update the values as needed.

The package.json file is an important part of any Node.js project, as it contains metadata about the project, such as its name, version, dependencies, and scripts. It also allows other developers to easily install and use your project's dependencies by running npm install command.