Codecademy Practice

Contact Book - Set Up

Challenge: We are going to build a contact book as a CLI app. The contacts will be stored in an array and will be lost when the application is closed.

Step by step instructions

We are going to create a contact book that runs in the terminal. When we run the app, it will print a menu with options, then it will read the option written by the user and call the right action.

Main user interface

• It prints this menu, where _ represents where the user prompt is. Please respect empty lines and spaces, ignore text color:

---------------------
  CONTACT BOOK
---------------------

  1) Exit the program

  Choose a menu option: _

• it clears the screen before printing the menu (to clear the screen, just write "\033[H\033[2J" to the output stream. Observe the double quotes)

• it reads an input from the user

• it validates the input. If the input is not a number, or is a number other than one, the input is invalid

• if the input is invalid it prints this in a new line and reads the input again. It keeps printing this until the input entered is valid:

Wrong input. Please try again: _

• If the input is valid, it returns it.

Instructions:

• Isolate all strings from the logic using constants

• require the user interface in your bin/app file, instantiate it and call the relevant methods

• run the app and make sure that the behaviour is expected

Controller

Create a controller class that will be the layer in between your user interface and the actions to perform.

• it tells the user interface to print the menu

• it receives the input from the user interface

• it selects the right action to perform according to the input (Exit in this case)

• it runs the action

Instructions:

• Use dependency injection to inject the user interface as a collaborator

• Pass the possible actions to the controller as an array in the constructor. For the exit action use the null object pattern and pass a NullAction, which does nothing.

• Update the bin/app file to require the controller, instantiate it and run the relevant methods

• Run the app and check it behaves as expected