prompt

A beautiful command-line prompt for node.js

Features

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

Usage

Using 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 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: [email protected]
  Command-line input received:
    username: some-user
    email: [email protected]

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 schema = {
    properties: {
      name: {
        pattern: /^[a-zA-Z\s\-]+$/,
        message: 'Name must be only letters, spaces, or dashes',
        required: true
      },
      password: {
        hidden: true
      }
    }
  };

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

  //
  // Get two properties from the user: email, password
  //
  prompt.get(schema, 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

prompt understands JSON-schema with a few extra parameters and uses revalidator for validation.

Here's an overview of the properties that may be used for validation and prompting controls:

  {
    description: 'Enter your password',     // Prompt displayed to the user. If not supplied name will be used.
    type: 'string',                 // Specify the type of input to expect.
    pattern: /^\w+$/,                  // Regular expression that input must be valid against.
    message: '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.
    required: true                        // If true, value entered must be non-empty.
    before: function(value) { return 'v' + value; } // Runs before node-prompt callbacks. It modifies user's input
  }

Alternatives to pattern include format and conform, as documented in revalidator.

Using type: 'array' has some special cases.

• description will not work in the schema if type: 'array' is defined.
• maxItems takes precedence over minItems.
• Arrays that do not have maxItems defined will require users to SIGINT (^C) before the array is ended.
• If SIGINT (^C) is triggered before minItems is met, a validation error will appear. This will require users to SIGEOF (^D) to end the input.

For more information on things such as maxItems and minItems, refer to the revalidator repository.

Alternate Validation API:

Prompt, in addition to iterating over JSON-Schema properties, will also happily iterate over an array of validation objects given an extra 'name' property:

  var prompt = require('../lib/prompt');

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

  //
  // Get two properties from the user: username and password
  //
  prompt.get([{
      name: 'username',
      required: true
    }, {
      name: 'password',
      hidden: true,
      conform: function (value) {
        return true;
      }
    }], function (err, result) {
    //
    // Log the results.
    //
    console.log('Command-line input received:');
    console.log('  username: ' + result.username);
    console.log('  password: ' + result.password);
  });

Backward Compatibility

Note that, while this structure is similar to that used by prompt 0.1.x, that the object properties use the same names as in JSON-Schema. prompt 0.2.x is backward compatible with prompt 0.1.x except for asynchronous validation.

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-override.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-override.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. 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, prompt supports ANSI color codes via the colors module for custom colors. For a very colorful example:

  var prompt = require("prompt");

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

  prompt.start();

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

If you don't want colors, you can set

var prompt = require('prompt');

prompt.colors = false;

Installation

  $ [sudo] npm install prompt

Running tests

  $ npm test

License: MIT

Author: Charlie Robbins

Contributors: Josh Holbrook, Pavan Kumar Sunkara