What is the role of helpers in Ruby on Rails? How can you use helpers to encapsulate reusable view logic?

In Ruby on Rails, helpers play a significant role in separating and encapsulating reusable view logic. They provide a way to centralize common functionality and make it available across multiple views, reducing code duplication and improving maintainability. Helpers are essentially modules that contain methods that can be called from within views, layouts, and even other helpers.

Here are some key aspects of the role of helpers in Ruby on Rails:

1. Encapsulating View Logic: Helpers allow you to encapsulate view-specific logic that goes beyond simple presentation of data. They provide a place to define methods that manipulate data, perform calculations, format values, generate HTML elements, and more. By encapsulating this logic in helpers, you can keep your views clean and focused on rendering the data without cluttering them with complex code.
2. Reusability: Helpers promote reusability by providing a way to define common functionality once and reuse it across different views or even different parts of the application. For example, if you have a formatting requirement that needs to be applied to multiple views, you can define a helper method to handle that formatting and call it from the respective views. This allows you to maintain consistency and avoid duplicating code.
3. Keeping Views Lightweight: By moving complex logic and calculations to helpers, you can keep your views lightweight and focused on their primary responsibility of rendering the data. Helpers help to achieve the separation of concerns principle by extracting non-view-related logic from the views, making them more readable and easier to maintain.
4. Abstraction: Helpers provide a level of abstraction, allowing you to create higher-level methods that encapsulate lower-level operations. This abstraction helps in simplifying the view code and making it more expressive. For example, you can create a helper method that generates a complex HTML structure based on certain input parameters, abstracting away the detailed HTML generation from the view.
5. Customization and Extensibility: Helpers can be customized and extended to meet specific application requirements. Rails allows you to create application-specific helpers that are automatically loaded and available within the views. Additionally, you can utilize third-party gems or libraries that provide helper modules, further expanding the capabilities and functionality of your helpers.

To use helpers in Ruby on Rails:

1. Create a Helper Module: In the app/helpers directory, create a new Ruby module that defines your helper methods. Typically, the module name should match the name of the view it is associated with, suffixed with "Helper" (e.g., `ProductsHelper` for the `products` views).
2. Define Helper Methods: Inside the helper module, define the methods that encapsulate the view logic. These methods can perform calculations, format data, generate HTML, or any other functionality required by the view.

Example:

```
ruby`module ProductsHelper
def format\_price(price)
"$#{sprintf('%.2f', price)}"
end

def product\_image\_tag(product)
image_tag(product.image_url, alt: product.name, class: 'product-image')
end
end`
```
3. Make Helpers Available in Views: By default, Rails automatically includes the relevant helper modules based on the name of the view. For example, the `ProductsHelper` module will be automatically available in the `products` views. You can then call the helper methods directly from the views.

Example usage in a view:

```
erb`<p>Price: <%= format_price(product.price) %></p>
<%= product_image_tag(product) %>`
```
Helpers are an integral part of Ruby on Rails and provide a convenient way to encapsulate reusable view logic. By using helpers effectively, you can enhance code reusability, maintainability, and keep your views focused on their primary responsibility of rendering data.