Tag: project-base-structure

When creating a new project, it can be helpful to start by defining the overall structure of your project and deciding on a suitable design pattern to use. There are many different design patterns that can be used in a variety of different contexts, so it is important to consider your project’s specific requirements and constraints when choosing a pattern.

Here are some steps you can follow to create a basic project structure and decide on a design pattern:

1. Define the scope and goals of your project. What are you trying to achieve, and what are the key features and functionality that your project needs to have?
2. Identify the main components of your project. Break down your project into smaller pieces that can be developed and tested separately.
3. Determine the relationships between the different components of your project. How do the different pieces fit together, and how will they interact with each other?
4. Research different design patterns that might be suitable for your project. Consider factors such as the complexity of your project, the need for flexibility and reuse, and the performance and scalability requirements of your project.
5. Evaluate the pros and cons of each design pattern and consider how well it fits with your project’s requirements and constraints.
6. Choose a design pattern that best meets the needs of your project, and plan out the overall structure of your project based on the chosen pattern.

It is important to keep in mind that design patterns are not a one-size-fits-all solution, and it is possible that your project may require a combination of different patterns to achieve the desired result. It is also important to be open to changing your design pattern as your project evolves and your understanding of the problem space deepens.

Quiz Game Example

interface Question {
  text: string;
  correctAnswer: string;
  possibleAnswers: string[];
}

class MultipleChoiceQuestion implements Question {
  constructor(
    public text: string,
    public correctAnswer: string,
    public possibleAnswers: string[]
  ) {}
}

class TrueFalseQuestion implements Question {
  constructor(
    public text: string,
    public correctAnswer: string,
    public possibleAnswers: string[] = ['True', 'False']
  ) {}
}

class QuestionFactory {
  static createQuestion(questionType: string, data: any): Question {
    switch (questionType) {
      case 'multiple-choice':
        return new MultipleChoiceQuestion(
          data.text,
          data.correctAnswer,
          data.possibleAnswers
        );
      case 'true-false':
        return new TrueFalseQuestion(data.text, data.correctAnswer);
      default:
        throw new Error(`Invalid question type: ${questionType}`);
    }
  }
}

const quizData = [
  {
    type: 'multiple-choice',
    text: 'What is the capital of France?',
    correctAnswer: 'Paris',
    possibleAnswers: ['Paris', 'London', 'Rome', 'Madrid']
  },
  {
    type: 'true-false',
    text: 'The Earth orbits the Sun.',
    correctAnswer: 'True'
  }
];

const quiz: Question[] = quizData.map((questionData) => {
  return QuestionFactory.createQuestion(questionData.type, questionData);
});

console.log(quiz);

In this example, the QuestionFactory class is used to create instances of Question objects based on the type of question being created. The createQuestion method takes a questionType parameter and a data object, and returns a new Question object of the appropriate type. The Question interface defines the common properties and methods that all Question objects should have, while the MultipleChoiceQuestion and TrueFalseQuestion classes provide specific implementations for different types of questions.

The quizData array contains data for two different questions, one of type 'multiple-choice' and one of type `’true-

false’. The mapfunction is used to iterate over thequizDataarray and create a newQuestionobject for each element using theQuestionFactory.createQuestionmethod. The resulting array ofQuestionobjects is then stored in thequiz` variable.

This example demonstrates how the Factory pattern can be used to create objects of different types based on input data, while maintaining a consistent interface for all objects and encapsulating the implementation details within the factory class. This can make it easier to maintain and extend the codebase, as new types of questions can be added simply by adding a new class and modifying the createQuestion method to handle the new type.

Online Store Example

Imagine that we are building an online store where customers can add items to their shopping cart and check out. The store sells three types of items: books, clothes, and electronics. Each type of item has its own set of specific properties (e.g. a book has an ISBN number and a page count, a piece of clothing has a size and a color, etc.), and we want to be able to add new types of items to the store in the future without having to change the existing code.

To solve this problem, we can use the Factory pattern to create a factory class that generates the appropriate objects based on the type of item. Here is how we might implement this using TypeScript:

interface Item {
  id: number;
  name: string;
  price: number;
  type: string;
}

interface Book extends Item {
  isbn: string;
  pageCount: number;
}

interface Clothes extends Item {
  size: string;
  color: string;
}

interface Electronics extends Item {
  manufacturer: string;
  model: string;
}

class ItemFactory {
  static createItem(type: string, data: any): Item {
    switch (type) {
      case 'book':
        return {
          id: data.id,
          name: data.name,
          price: data.price,
          type: 'book',
          isbn: data.isbn,
          pageCount: data.pageCount
        } as Book;
      case 'clothes':
        return {
          id: data.id,
          name: data.name,
          price: data.price,
          type: 'clothes',
          size: data.size,
          color: data.color
        } as Clothes;
      case 'electronics':
        return {
          id: data.id,
          name: data.name,
          price: data.price,
          type: 'electronics',
          manufacturer: data.manufacturer,
          model: data.model
        } as Electronics;
      default:
        throw new Error(`Invalid item type: ${type}`);
    }
  }
}

const book: Book = ItemFactory.createItem('book', {
  id: 1,
  name: 'The Great Gatsby',
  price: 15,
  isbn: '978-0