How to Run JavaScript in a Terminal: The Expert's Way (2024)

JavaScript—the ubiquitous language of the web—is not just for front-end development anymore. Its versatility and growing ecosystem make it a powerhouse for backend applications, automation tools, and even mobile development. 

However, how do you tap into this potential without the confines of a browser? Enter the terminal, your command-line gateway to a world of possibilities. This guide will reveal the secrets, showing you how to run JavaScript in your terminal and unlock its hidden potential.

What Is JavaScript? Why Is It Useful for Web Development and Other Applications?

Javascript is a dynamic programming language that can run on a web browser or a server. JavaScript can manipulate a web page’s HTML and CSS elements, add interactivity, and communicate with web servers and databases. Moreover, it allows the development of responsive web applications that work seamlessly on any device or platform.

One of the most significant benefits of JavaScript in web development is its ability to make web pages more engaging, interactive, and user-friendly. With JavaScript, you can create animations, validate forms, handle user events, fetch data, and update the web page without reloading. It can also be used to develop web frameworks and libraries that make web development more straightforward and efficient.

JavaScript is not limited to web development alone. It can run outside the web browser using a JavaScript engine to access system resources and functionalities. 

For instance, Node.js is a powerful JavaScript engine that can run on a server and provide features like file system, network, and database access. With Node.js, you can create backend applications that handle requests, process data, and communicate with other servers and services. All in all, JavaScript is a versatile language used for various applications beyond web development.

What Is a Terminal? Can JavaScript Be Run in a Terminal?

A terminal program is a command-line interface that allows users to interact with the operating system using text commands. It provides a wealth of functionalities, such as navigating the file system, installing software packages, configuring settings, and running programs. With a terminal, you can write and run code and scripts in various programming languages, including JavaScript. 

Running JavaScript in a terminal is extremely useful for testing, debugging, and experimenting with code and features. It also enables you to create and run JavaScript command-line tools and applications, greatly enhancing your workflow and productivity. 

Overall, a terminal program is a powerful tool for developers and system administrators, allowing them to accomplish complex tasks and automate routine processes through simple text commands.

How to Run JavaScript in a Terminal: 3 Common Ways

There are many ways of running JavaScript in a terminal. However, in this article, we will focus on three common and easy methods: Node.js, JSC,js, and VS Code.

Using Node.js: The Backend of JavaScript

Node.js is a powerful JavaScript engine that can be used to run server-side applications and provide access to features such as file systems, networks, and databases. Additionally, you can use Node.js to execute JavaScript code in a terminal using either a REPL (Read-Eval-Print Loop) or script mode.

Before running JavaScript code in a terminal using Node.js, you need to install it on your system first. You can download and install Node.js from its official website or use a package manager like npm or Homebrew. 

After installing Node.js successfully, you can open a terminal and type node to enter the REPL mode. After that, you can type and execute JavaScript code line by line and see the results immediately. For example, you can type console.log("Hello world!") and press Enter to see the output Hello world! in the terminal. To exit the REPL mode, type .exit or press Ctrl + C twice.

In addition, you can run JavaScript code by creating a JavaScript file and running it using the node command. For instance, you can create a file named hello.js and write the following code in it:

​​console.log("Hello world!");

Then, you can save the file and run it in a terminal by typing node hello.js. If successful, you will see the output Hello world! in the terminal.

JSC.js—The Hidden Gem of JavaScript in the Terminal

JSC.js is a JavaScript engine that Safari and other WebKit-based browsers use. In addition to running JavaScript code in a browser, JSC.js can execute JavaScript code in a terminal using a REPL or script mode.

To execute JavaScript code using JSC.js in a terminal, you must first install it on your system. JSC.js is typically pre-installed on macOS and Linux systems. However, you can install it manually or via a package manager like Homebrew.

How to run JavaScript code in your terminal using JSC,js? First, open a terminal and type jsc to enter the REPL mode. Then, you can type and execute JavaScript code line by line and see the results immediately. For instance, you can type Math.sqrt(16) and press Enter to see the output 4 in the terminal. To exit the REPL mode, type quit() or press Ctrl + D.

Additionally, you can run JavaScript code by creating a JavaScript file and running it using the jsc command. For example, you can create a file named goodbye.js and write the following code in it:

print("Goodbye world!");

Finally, you can save the file and run it in a terminal by typing jsc goodbye.js. You will see the output Goodbye world! in the terminal if successful.

How to Run JS Files in VS Code

VS Code is a widely used and robust code editor that supports numerous programming languages, including JavaScript. Additionally, it has a built-in feature or an extension to run JavaScript code in a terminal. 

Before learning how to run JavaScript in your terminal using VS Code, you first need to have VS Code installed on your system. You can download and install it from its official website or use a package manager like Homebrew. 

To run JavaScript code in a terminal using the built-in feature of VS Code, you need to follow these steps:

• Open a JavaScript file in VS Code.
• Press Ctrl + Shift + P to open the Command Palette.
• Type Terminal: Run Active File in Active Terminal and press Enter.
• A terminal will open in VS Code and run the JavaScript file.

In addition, you can use an extension of VS Code to run JavaScript in a terminal:

• Open a JavaScript file in VS Code.
• Install an extension that can run JavaScript code in a terminal, such as Code Runner or Quokka.js.
• Use the extension’s commands or shortcuts to run the JavaScript file in a terminal.

A Recap of How to Run JavaScript in Terminals

In this article, we have learned what JavaScript is, what a terminal is, and how to run JavaScript in a terminal using three different methods: Node.js, JSC.js, and VS Code. 

Running JavaScript in a terminal opens doors to a vast world of possibilities. Whether you are building backend applications, automating tasks, or simply exploring the language’s power, the terminal becomes your playground. So, dive in, experiment, and unleash the full potential of JavaScript—one line of code at a time.

Remember, this is just the beginning. As you delve deeper, you will discover even more ways to leverage JavaScript in your terminal, from advanced package managers like npm to building complex command-line interfaces. Therefore, it is time for you to open that terminal window, type your first line of JavaScript code, and get ready to be amazed by what you can achieve.

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