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Readline Module | Console Applications
Backend Development with Node.js and Express.js
course content

Course Content

Backend Development with Node.js and Express.js

Backend Development with Node.js and Express.js

1. Introduction
2. Console Applications
3. Express.js Framework
4. Developing REST API

bookReadline Module

👋 Getting Started with Readline

The Readline module is a built-in module in Node.js that simplifies reading input from the user in an interactive manner. It's often used to create prompts, collect user responses, and build interactive question-answer sessions in the command-line interface.

📖 Understanding the Readline Module

Before diving into a real-world example, let's explore the core concepts and methods provided by the Readline module.

Creating a Readline Interface

To use the Readline module, we typically start by creating a Readline interface that manages input and output streams. Here's how we create an interface:

  • const rl represents the Readline interface;
  • readline.createInterface({ input: process.stdin, output: process.stdout }) sets up the interface to read from the standard input (process.stdin) and write to the standard output (process.stdout).

Collecting User Input

Once we have a Readline interface, we can use it to collect user input. The most common method for this purpose is rl.question():

  • rl.question("Please enter your name: ", (name) => { ... }) prompts the user for input with the provided message;
  • The callback function (name) => { ... } is executed when the user enters their response;
  • name contains the user's input.

Managing the Interface

It's important to close the Readline interface when we're done with it. We can do this using rl.close().

🔧 Creating an Interactive Prompt

Now that we've covered the basics let's put our knowledge to use and create a fun command-line fortune teller. Users will enter their names, and the application will generate a random fortune message.

Here's the code example from the video:

In this example, we've applied the above concepts to create an interactive command-line application. Users are prompted for input, and the application generates random responses. The Readline module simplifies user interaction in the command-line interface, making it ideal for creating interactive CLI applications.

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Section 2. Chapter 7
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