promptly

What is promptly?

The 'promptly' npm package is a simple utility for prompting user input in Node.js applications. It provides a straightforward way to ask for user input from the command line, with support for validation, default values, and hidden input for sensitive information.

What are promptly's main functionalities?

Basic Prompt

This feature allows you to prompt the user for input and then use that input in your application. The example code asks the user for their name and then greets them.

const promptly = require('promptly');

(async () => {
  const name = await promptly.prompt('Enter your name: ');
  console.log(`Hello, ${name}!`);
})();

Prompt with Default Value

This feature allows you to provide a default value for the prompt. If the user does not enter anything, the default value will be used. The example code sets 'Anonymous' as the default name.

const promptly = require('promptly');

(async () => {
  const name = await promptly.prompt('Enter your name: ', { default: 'Anonymous' });
  console.log(`Hello, ${name}!`);
})();

Hidden Input

This feature allows you to prompt the user for input without displaying what they type on the screen. This is useful for sensitive information like passwords. The example code asks for a password and hides the input.

const promptly = require('promptly');

(async () => {
  const password = await promptly.prompt('Enter your password: ', { silent: true });
  console.log('Password received.');
})();

Input Validation

This feature allows you to validate the user's input before accepting it. The example code validates that the input is a positive integer representing the user's age.

const promptly = require('promptly');

(async () => {
  const age = await promptly.prompt('Enter your age: ', {
    validator: (value) => {
      const age = parseInt(value, 10);
      if (isNaN(age) || age <= 0) {
        throw new Error('Invalid age');
      }
      return age;
    }
  });
  console.log(`You are ${age} years old.`);
})();

Other packages similar to promptly

inquirer

Inquirer.js is a powerful and flexible library for creating interactive command-line interfaces. It supports a wide range of prompt types, including input, confirm, list, rawlist, expand, checkbox, password, and editor. Compared to promptly, Inquirer.js offers more advanced features and customization options.

readline-sync

Readline-sync is a synchronous library for reading user input from the command line. It provides basic functionality for prompting user input, similar to promptly, but operates synchronously, making it simpler to use in some cases. However, it lacks some of the advanced features and flexibility of promptly.

prompt

The 'prompt' package is another library for prompting user input in Node.js. It supports various input types, validation, and default values. While it offers similar functionality to promptly, it has a more complex API and additional features like schema-based prompts.

README

promptly

Simple command line prompting utility.

Installation

$ npm install promptly

API

.prompt(message, [opts], fn)

Prompts for a value, printing the message and waiting for the input.
When done, calls fn with error and value.

Default options:

{
    // The default value. If not supplied, the input is mandatory
    'default': null,
    // Automatically trim the input
    'trim': true,
    // A validator or an array of validators.
    'validator': null,
    // Automatically retry if a validator fails
    'retry': true,
    // Do not print what the user types
    'silent': false,
    // Input and output streams to read and write to
    'input': process.stdin,
    'output': process.stdout
}

The validators have two purposes:

function (value) {
    // Validation example, throwing an error when invalid
    if (value.length !== 2) {
        throw new Error('Length must be 2');
    }

    // Parse the value, modifying it
    return value.replace('aa', 'bb');
}

Example usages

Ask for a name:

promptly.prompt('Name: ', function (err, value) {
    // err is always null in this case, because no validators are set
    console.log(value);
});

Ask for a name with a constraint (non-empty value and length > 2):

var validator = function (value) {
    if (value.length < 2) {
        throw new Error('Min length of 2');
    }

    return value;
};

promptly.prompt('Name: ', { validator: validator }, function (err, value) {
    // Since retry is true by default, err is always null
    // because promptly will be prompting for a name until it validates
    // Between each prompt, the error message from the validator will be printed
    console.log('Name is:', value);
});

Same as above but do not retry automatically:

var validator = function (value) {
    if (value.length < 2) {
        throw new Error('Min length of 2');
    }

    return value;
};

promptly.prompt('Name: ', { validator: validator, retry: false }, function (err, value) {
    if (err) {
        console.error('Invalid name:', e.message);
        // Manually call retry
        // The passed error has a retry method to easily prompt again.
        return err.retry();
    }

    console.log('Name is:', value);
});

.confirm(message, [opts], fn)

Ask the user to confirm something.
Calls fn with error and value (true or false).

Truthy values are: y, yes and 1.
Falsy values are n, no, and 0.
Comparison is made in a case insensitive way.

Example usage:

promptly.confirm('Are you sure? ', function (err, value) {
    console.log('Answer:', value);
});

.choose(message, choices, [opts], fn)

Ask the user to choose between multiple choices (array of choices).
Calls fn with error and value.

Example usage:

promptly.choose('Do you want an apple or an orange? ', ['apple', 'orange'], function (err, value) {
    console.log('Answer:', value);
});

.password(message, [opts], fn)

Prompts for a password, printing the message and waiting for the input.
When available, calls fn with error and value.

The available options are the same, except that trim and silent default to false and default is an empty string (to allow empty passwords).

Example usage:

promptly.password('Type a password: ', function (err, value) {
    console.log('Password is:', value);
});

License

Released under the MIT License.