Presentation Model Pattern

1. Introduction

The Presentation Model Pattern is a design pattern that separates the presentation layer from the underlying model in an application. This allows for a cleaner architecture, making it easier to manage the user interface without being tightly coupled to the business logic.

2. Key Concepts

• The Presentation Model serves as an intermediary between the view and the model.
• It encapsulates the state and behavior of the UI, allowing for better testability and maintainability.
• Changes in the model can be reflected in the presentation model, and consequently in the view.

3. Implementation Steps

1. Create a model representing the data and business logic.
2. Develop a presentation model that binds to the view and listens for changes in the model.
3. Implement the view to display information from the presentation model.
4. Ensure two-way data binding between the UI and presentation model.
5. Handle user interactions in the presentation model to update the model accordingly.

class Model {
    constructor() {
        this.data = "Hello, World!";
    }
}

class PresentationModel {
    constructor(model) {
        this.model = model;
        this.viewData = this.model.data;
    }

    updateViewData(newData) {
        this.viewData = newData;
        this.model.data = newData; // Update model
    }
}

const model = new Model();
const presentationModel = new PresentationModel(model);
presentationModel.updateViewData("Hello, Presentation Model!");
console.log(presentationModel.viewData); // Output: Hello, Presentation Model!
                

4. Best Practices

• Keep the presentation model lightweight; it should only contain presentation logic.
• Use data binding techniques for efficient synchronization between the model and the view.
• Write unit tests for your presentation model to ensure its correctness.

5. FAQ