index.js

class Exhibit {
  //This class holds information about Exhibits of animals to be featured at Zoos.
  constructor(animal, population) {
    this.animal = animal;
    this.population = population;
    //This constructor takes the name of the animal and the population of that animal as parameters
  }
}

class Zoo {
  //The Zoo class will hold Exhibits of animals, and each Zoo has its own name.
  constructor(zooName) {
    this.zooName = zooName;
    this.exhibits = [];
    //This constructor method sets the name of the Zoo to what was input by the user
    //The array for exhibits is declared but not assigned a value yet, as it will be filled later by the user
  }

  addExhibit(exhibit) {
    if (exhibit instanceof Exhibit) {
      this.exhibits.push(exhibit);
    } else {
      throw new Error(
        `You can only add an instance of Exhibit. Argument is not a exhibit: ${exhibit}`
      );
      //If the user tries to add something that isn't an Exhibit to a Zoo, then an error is thrown
    }
  }
}

class Menu {
  constructor() {
    this.Zoos = [];
    this.selectedZoo = null;
    //Menu objects will hold an array that contains all of the Zoo objects (which hold their own exhibits)
    //selectedZoo is initialized as null because this program requires the use of a property which will be updated with user input.
    //Later, selectedZoo will hold a Zoo object.
  }

  start() {
    let selection = this.showMainMenuOptions();
    //First showMainMenuOptions is called, causing a prompt to appear when the user runs this program
    //The user's input in that prompt is assigned to the selection variable, which will be fed into a switch statement
    //Based on the value of the selection variable, the program will decide what method of the Menu class to execute next.
    while (selection != 0) {
      switch (selection) {
        case "1":
          this.createZoo();
          break;
        case "2":
          this.editZoo();
          break;
        case "3":
          this.deleteZoo();
          break;
        case "4":
          this.displayZoos();
          break;
        default:
          selection = 0;
      }
      selection = this.showMainMenuOptions();
    }

    alert("Goodbye!");
    //If the user inputs 0 at the main menu, the application will exit
  }

  showMainMenuOptions() {
    return prompt(`
    0) Exit
    1) Create new Zoo
    2) Edit Zoo
    3) Delete Zoo
    4) Display all Zoos
    `);
    //This method shows the user a prompt with a list of options available for this program
    //showMainMenuOptions is called by start(), and whatever is input in this prompt will be returned to start() to select one of the options
  }

  displayZoos() {
    let zooString = "";
    for (let i = 0; i < this.Zoos.length; i++) {
      zooString += i + ") " + this.Zoos[i].zooName + "\n";
      if (this.Zoos[i].exhibits >= 1) {
        zooString += "\t" + "Featuring these exhibits: " + "\n";
      }
      for (let j = 0; j < this.Zoos[i].exhibits.length; j++) {
        zooString +=
          "\t" +
          j +
          ") " +
          this.Zoos[i].exhibits[j].animal +
          " with a population of " +
          this.Zoos[i].exhibits[j].population +
          "\n";
      }
    }
    //These loops will compile a list of all Zoos stored in the menu application as well as the exhibits of those Zoos and then display them to the user in an alert
    alert(zooString);
  }

  createZoo() {
    let zooName = prompt("Enter name for new Zoo:");
    this.Zoos.push(new Zoo(zooName));
    //createZoo prompts the user to input a name for the new Zoo object they will be creating
  }

  deleteZoo() {
    let listZoos = "";
    for (let i = 0; i < this.Zoos.length; i++) {
      listZoos += i + ") " + this.Zoos[i].zooName + "\n";
    }
    //This loop gathers a numbered list of the Zoos created by the user

    let index = prompt(`
    Existing Zoos:
    ${listZoos}
    ----
    Please enter the index of the Zoo you wish to delete:
    `);
    if (index > -1 && index < this.Zoos.length) {
      this.Zoos.splice(index, 1);
    }
    //Then after the list of existing Zoos has been compiled, the list is shown to the user within a prompt
    //This prompt then asks the user to input the index of the Zoo they wish to delete
  }

  editZoo() {
    //--

    let listZoos = "";
    for (let i = 0; i < this.Zoos.length; i++) {
      listZoos += i + ") " + this.Zoos[i].zooName + "\n";
    }

    let index = prompt(`
    Existing Zoos:
    ${listZoos}
    ----
    Please enter the index of the Zoo you wish to edit details of:
    `);
    //This prompt shows the user all existing Zoos and asks them to input the index of the Zoo they want to edit details of

    //--

    if (index > -1 && index < this.Zoos.length) {
      this.selectedZoo = this.Zoos[index];
      //Set the selectedZoo property of the current Menu object to the particular Zoo object specified by the user's input
      let description =
        "Zoo Name: " +
        this.selectedZoo.zooName +
        "\n" +
        "Has these animals: " +
        "\n";

      for (let i = 0; i < this.selectedZoo.exhibits.length; i++) {
        description +=
          i +
          ") " +
          this.selectedZoo.exhibits[i].animal +
          " with a population of " +
          this.selectedZoo.exhibits[i].population +
          "\n";
      }
      //Gather the exhibits featured at the user-specified Zoo and also the population of those exhibits
      let selection = this.showZooMenuOptions(description);
      //Pass all of the information regarding the Zoo selected by the user into the showZooMenuOptions method
      switch (selection) {
        case "1":
          this.createExhibit();
          break;
        case "2":
          this.deleteExhibit();
          break;
      }
    }
  }

  showZooMenuOptions(ZooInfo) {
    return prompt(`
    0) back
    1) create exhibit
    2) delete exhibit
    --------
    ${ZooInfo}
    `);
    //showZooMenuOptions displays a series of options the user can pick from followed by the information about the Zoo they selected earlier
  }

  createExhibit() {
    let animal = prompt("Enter animal for new exhibit:");
    let population = prompt(" Enter population for new exhibit:");
    this.selectedZoo.addExhibit(new Exhibit(animal, population));
    //createExhibit asks the user to input an animal name and the population of that animal to be featured as an exhibit for the Zoo they selected earlier
  }

  deleteExhibit() {
    let listExhibits = "";
    for (let i = 0; i < this.selectedZoo.exhibits.length; i++) {
      listExhibits += i + ") " + this.selectedZoo.exhibits[i].animal + " - "+ this.selectedZoo.exhibits[i].population + "\n";
    }
    //Gather a list of exhibits that exist in the user's selected Zoo
    let index = prompt(`Existing exhibits:
    ${listExhibits}
    ----
    Please enter the index of the exhibit you wish to delete:"
    `);
    //Prompt the user with all existing exhibits of that Zoo along with instructions for the user to input an idex
    //That index input by the user will indicate which exhibit to delete

    //let index = prompt("Enter the index of the exhibit you wish to delete: ");
    if (index > -1 && index < this.selectedZoo.exhibits.length) {
      this.selectedZoo.exhibits.splice(index, 1);
    }
    //deleteExhibit asks the user to input the index of the exhibit they want to delete from the Zoo they selected earlier
  }
}

let menu = new Menu();
//In order for this program to actually do something, an instance of the Menu object has to be created
menu.start();
//Then, with that new menu instance, start() is invoked, which will lead the user through a series of prompts to use the menu application