Prompts

Prompts helps you to add beautiful and user-friendly forms to your command-line applications, with browser-like features including label text, help text, validation, and inline errors.

It was originally inspired by the Laravel Prompts package.

Install the gem and add to the application's Gemfile by executing:

bundle add prompts

If bundler is not being used to manage dependencies, install the gem by executing:

gem install prompts

Prompts aims to provide beautiful and user-friendly forms for your command-line applications while keeping both the API and the implementation simple. This means Prompts is built with constraints in mind.

In order to minimize complexity, we build on top of the excellent reline gem to provide a full-featured text input. Similarly, the text input is always rendered at the bottom of the screen. And inputing text is the only way to interact with the form.

In this way, this new library is similar to Charm's Huh library when used in "accessible" mode. But, with some UX improvements added to this interaction. Instead of simply appending new fields to the screen, Prompts' forms act like wizards 🧙‍♂️. Each field gets its own screen, and on each render loop, the screen is reset and repainted.

Finally, to keep internals simple, Prompts expects users to build and provide their own ANSI-formatted strings. However, we do make available the fmt gem as the recommended way to generate well formatted ANSI strings.

A Text prompt will prompt the user with the given question, accept their input, and then return it:

name = Prompts::TextPrompt.ask(label: "What is your name?")

which generates a terminal screen like this (this representation doesn't show color):

   What is your name? (Press Enter to submit)
   Type your response and press Enter ⏎

   > |

You may also include a default value and an informational hint:

name = Prompts::TextPrompt.ask(
  label: "What is your name?",
  default: "John Doe",
  hint: "This will be displayed on your profile."
)

which generates a terminal screen like this (this representation doesn't show color):

   What is your name? (Press Enter to submit)
   This will be displayed on your profile.

   > John Doe|

If you require a value to be entered, you may pass the required argument:

name = Prompts::TextPrompt.ask(
  label: "What is your name?",
  required: true
)

If you would like to customize the validation message, you may also pass a string:

name = Prompts::TextPrompt.ask(
  label: "What is your name?",
  required: "Your name is required."
)

Finally, if you would like to perform additional validation logic, you may pass a block/proc to the validate argument:

name = Prompts::TextPrompt.ask(
  label: "What is your name?",
  validate: ->(value) do
    if value.length < 3
      "The name must be at least 3 characters."
    elsif value.length > 255
      "The name must not exceed 255 characters."
    end
  end
)

The block will receive the value that has been entered and may return an error message, or nil if the validation passes.

If you need the user to select from a predefined set of choices, you may use the Select prompt:

role = Prompts::SelectPrompt.ask(
  label: "What role should the user have?",
  options: ["Member", "Contributor", "Owner"]
)

which generates a terminal screen like this (this representation doesn't show color):

   What role should the user have? (Enter the number of your choice)
   Type your response and press Enter ⏎
   1. Member
   2. Contributor
   3. Owner

   > |

You may also include a default value and an informational hint:

role = Prompts::SelectPrompt.ask(
  label: "What role should the user have?",
  options: ["Member", "Contributor", "Owner"],
  default: "Owner",
  hint: "The role may be changed at any time."
)

which generates a terminal screen like this (this representation doesn't show color):

   What role should the user have? (Enter the number of your choice)
   The role may be changed at any time.
   1. Member
   2. Contributor
   3. Owner

   > 3|

You may also pass a hash to the options argument to have the selected key returned instead of its value:

role = Prompts::SelectPrompt.ask(
  label: "What role should the user have?",
  options: {
    member: "Member",
    contributor: "Contributor",
    owner: "Owner",
  },
  default: "owner"
)

Unlike other prompt classes, the SelectPrompt doesn't accept the required argument because it is not possible to select nothing. However, you may pass a block/proc to the validate argument if you need to present an option but prevent it from being selected:

role = Prompts::SelectPrompt.ask(
  label: "What role should the user have?",
  options: {
    member: "Member",
    contributor: "Contributor",
    owner: "Owner",
  },
  validate: ->(value) do
    if value == "owner" && User.where(role: "owner").exists?
      "An owner already exists."
    end
  end
)

If the options argument is a hash, then the block will receive the selected key, otherwise it will receive the selected value. The block may return an error message, or nil if the validation passes.

If you need to ask the user for a "yes or no" confirmation, you may use the ConfirmPrompt. Users may press y or n (or Y or N) to select their response. This function will return either true or false.

confirmed = Prompts::ConfirmPrompt.ask(label: "Do you accept the terms?")

which generates a terminal screen like this (this representation doesn't show color):

   Do you accept the terms? (Press Enter to submit)

   Choose [y/n]: |

You may also include a default value and an informational hint:

confirmed = Prompts::ConfirmPrompt.ask(
  label: "Do you accept the terms?",
  default: false,
  hint: "The terms must be accepted to continue.",
)

which generates a terminal screen like this (this representation doesn't show color):

   Do you accept the terms? (Press Enter to submit)
   The terms must be accepted to continue.

   Choose [y/N]: |

If necessary, you may require your users to select "Yes" by passing the required argument:

confirmed = Prompts::ConfirmPrompt.ask(
  label: "Do you accept the terms?",
  required: true
)

If you would like to customize the validation message, you may also pass a string:

confirmed = Prompts::ConfirmPrompt.ask(
  label: "Do you accept the terms?",
  required: "You must accept the terms to continue."
)

The PausePrompt may be used to display informational text to the user and wait for them to confirm their desire to proceed by pressing the Enter / Return key:

Prompts::PausePrompt.ask

which generates a terminal screen like this (this representation doesn't show color):

   Press Enter ⏎ to continue... |

Often, you will have multiple prompts that will be displayed in sequence to collect information before performing additional actions. You may use the Prompts::Form class to create a grouped set of prompts for the user to complete:

responses = Prompts::Form.submit do |form|
  form.text(
    label: "What is your name?",
    required: true
  )
  form.select(
    label: "What role should the user have?",
    options: {
      member: "Member",
      contributor: "Contributor",
      owner: "Owner",
    }
  )
  form.confirm(
    label: 'Do you accept the terms?'
  )
end

The submit method will return a numerically indexed hash containing all of the responses from the form's prompts. However, you may provide a name for each prompt via the name argument. When a name is provided, the named prompt's response may be accessed via that name:

responses = Prompts::Form.submit do |form|
  form.text(
    label: "What is your name?",
    required: true,
    name: :name
  )
  form.select(
    label: "What role should the user have?",
    options: {
      member: "Member",
      contributor: "Contributor",
      owner: "Owner",
    },
    name: :role
  )
  form.confirm(
    label: 'Do you accept the terms?',
    name: :terms
  )
end

User.create(
  name: responses[:name],
  role: responses[:role],
  terms: responses[:terms]
)

After checking out the repo, run bin/setup to install dependencies. Then, run rake test to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and the created tag, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/fractaledmind/prompts. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.

The gem is available as open source under the terms of the MIT License.

Everyone interacting in the Prompts project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.