read

What is read?

The 'read' npm package is a simple utility for reading user input from the command line. It is often used to prompt users for information in a synchronous manner, making it useful for command-line applications and scripts.

What are read's main functionalities?

Basic User Input

This feature allows you to prompt the user for input and handle the response. The example code asks the user for their name and then prints a greeting.

const read = require('read');

const options = {
  prompt: 'What is your name? '
};

read(options, function(err, result) {
  if (err) {
    console.error('Error:', err);
  } else {
    console.log('Hello, ' + result + '!');
  }
});

Password Input

This feature allows you to prompt the user for sensitive information like passwords without displaying the input on the screen. The example code asks the user for a password and confirms receipt without showing the password.

const read = require('read');

const options = {
  prompt: 'Enter your password: ',
  silent: true
};

read(options, function(err, result) {
  if (err) {
    console.error('Error:', err);
  } else {
    console.log('Password received.');
  }
});

Default Values

This feature allows you to provide a default value for the user input. The example code asks the user for their favorite color and defaults to 'blue' if no input is provided.

const read = require('read');

const options = {
  prompt: 'What is your favorite color? ',
  default: 'blue'
};

read(options, function(err, result) {
  if (err) {
    console.error('Error:', err);
  } else {
    console.log('Your favorite color is ' + result + '.');
  }
});

Other packages similar to read

prompt

The 'prompt' package is a more feature-rich alternative to 'read'. It supports validation, default values, and complex prompts with multiple fields. It is more suitable for applications that require more sophisticated user input handling.

inquirer

The 'inquirer' package is another alternative that provides a more interactive experience. It supports various types of prompts like lists, checkboxes, and password fields. It is ideal for building interactive command-line interfaces.

readline-sync

The 'readline-sync' package allows for synchronous reading of user input from the command line. It is similar to 'read' but provides more control over the input process, including the ability to handle multiple lines of input.

README

For reading user input from stdin.

USAGE

var read = require("read")
read(options, callback)

The callback gets called with either the user input, or the default specified, or an error, in the traditional callback(error, result) node style.

OPTIONS

Every option is optional.

• prompt What to write to stdout before reading input.
• silent Don't echo the output as the user types it.
• num Max number of chars to read from terminal.
• timeout Number of ms to wait for user input before giving up.
• default The default value if the user enters nothing.
• stdin Readable stream to get input data from. (default process.stdin)
• stdout Writeable stream to write prompts to. (default: process.stdout)

If silent is true, or num is set, and the input is a TTY, then read will set raw mode, and read character by character.

At this time, backspace and arrow keys are not supported very well. It's probably not too hard to add support for this, perhaps using node's built-in readline module.

CONTRIBUTING

Patches welcome.

BUGS

In node 0.6.0 through 0.6.5, you must explicitly call process.stdin.destroy() or process.exit() when you know that your program is done reading, or else it will keep the event loop running forever.

See: https://github.com/joyent/node/issues/2257