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a beautiful command-line prompt for node.js

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README.md

node-prompt

A beautiful command-line prompt for node.js

Features

  • prompts the user for input
  • supports validation and defaults
  • hides passwords

Installation

Installing npm (node package manager)

curl http://npmjs.org/install.sh | sh

Installing prompt

[sudo] npm install prompt

Usage

Using node-prompt is relatively straight forward. There are two core methods you should be aware of: prompt.get() and prompt.addProperties(). There methods take strings representing property names in addition to objects for complex property validation (and more). There are a number of examples that you should examine for detailed usage.

Getting Basic Prompt Information

Getting started with node-prompt is easy. Lets take a look at examples/simple-prompt.js:

var prompt = require('prompt');

//
// Start the prompt
//
prompt.start();

//
// Get two properties from the user: username and email
//
prompt.get(['username', 'email'], function (err, result) {
  //
  // Log the results.
  //
  console.log('Command-line input received:');
  console.log('  username: ' + result.username);
  console.log('  email: ' + result.email);
})

This will result in the following command-line output:

$ node examples/simple-prompt.js 
prompt: username: some-user
prompt: email: some-user@some-place.org
Command-line input received:
  username: some-user
  email: some-user@some-place.org

Prompting with Validation, Default Values, and More (Complex Properties)

In addition to prompting the user with simple string prompts, there is a robust API for getting and validating complex information from a command-line prompt. Here's a quick sample:

var properties = [
  {
    name: 'name', 
    validator: /^[a-zA-Z\s\-]+$/,
    warning: 'Name must be only letters, spaces, or dashes',
    empty: false
  },
  {
    name: 'password',
    hidden: true
  }
];

//
// Start the prompt
//
prompt.start();

//
// Get two properties from the user: email, password
//
prompt.get(properties, function (err, result) {
  //
  // Log the results.
  //
  console.log('Command-line input received:');
  console.log('  name: ' + result.name);
  console.log('  password: ' + result.password);
});

Pretty easy right? The output from the above script is:

$ node examples/property-prompt.js
prompt: name: nodejitsu000
error:  Invalid input for name
error:  Name must be only letters, spaces, or dashes
prompt: name: Nodejitsu Inc
prompt: password: 
Command-line input received:
  name: Nodejitsu Inc
  password: some-password  

Valid Property Settings

node-prompt uses a simple property system for performing a couple of basic validation operations against input received from the command-line. The motivations here were speed and simplicity of implementation to integration of pseudo-standards like JSON-Schema were not feasible.

Lets examine the anatomy of a prompt property:

{
  message: 'Enter your password',     // Prompt displayed to the user. If not supplied name will be used.
  name: 'password'                    // Key in the JSON object returned from `.get()`.
  validator: /^\w+$/                  // Regular expression that input must be valid against.
  warning: 'Password must be letters' // Warning message to display if validation fails.
  hidden: true                        // If true, characters entered will not be output to console.
  default: 'lamepassword'             // Default value to use if no value is entered.
  empty: false                        // If false, value entered must be non-empty.
}

skipping prompts

Sometimes power users may wish to skip promts and specify all data as command line options. if a value is set as a property of prompt.override prompt will use that instead of prompting the user.

//prompt-everride.js

var prompt = require('prompt'),
    optimist = require('optimist')

//
// set the overrides
//
prompt.override = optimist.argv

//
// Start the prompt
//
prompt.start();

//
// Get two properties from the user: username and email
//
prompt.get(['username', 'email'], function (err, result) {
  //
  // Log the results.
  //
  console.log('Command-line input received:');
  console.log('  username: ' + result.username);
  console.log('  email: ' + result.email);
})

//: node prompt-everride.js --username USER --email EMAIL

Adding Properties to an Object

A common use-case for prompting users for data from the command-line is to extend or create a configuration object that is passed onto the entry-point method for your CLI tool. node-prompt exposes a convenience method for doing just this:

var obj = {
  password: 'lamepassword',
  mindset: 'NY'
}

//
// Log the initial object.
//
console.log('Initial object to be extended:');
console.dir(obj);

//
// Add two properties to the empty object: username and email
//
prompt.addProperties(obj, ['username', 'email'], function (err) {
  //
  // Log the results.
  //
  console.log('Updated object received:');
  console.dir(obj);
});

Customizing your prompt

Aside from changing property.message, you can also change prompt.message and prompt.delimiter to change the appearance of your prompt.

The basic structure of a prompt is this:

prompt.message + prompt.delimiter + property.message + prompt.delimiter;

The default prompt.message is "prompt," the default prompt.delimiter is ": ", and the default property.message is property.name. Changing these allows you to customize the appearance of your prompts! In addition, node-prompt supports ANSI color codes via the colors module for custom colors. For a very colorful example:

var prompt = require("prompt");
//
// The colors module adds color properties to String.prototype
//
require("colors");

//
// Setting these properties customizes the prompt.
//
prompt.message = "Question!".rainbow;
prompt.delimiter = "><".green;

prompt.start();

prompt.get([{ name: "name",
              message: "What is your name?".magenta }], function (err, result) {
  console.log("You said your name is: ".cyan + result.name.cyan);
});

Running tests

vows test/*-test.js --spec

Author: Charlie Robbins

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