View helpers in Ruby on Rails - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a view helper in Rails?

A view helper is a method used to keep view templates clean by moving complex logic or reusable code into helper modules. It helps format data or generate HTML in views.

beginner

Where do you define custom view helpers in a Rails app?

You define custom view helpers inside modules in the app/helpers directory. These helpers are automatically available in views.

beginner

How do you use a helper method inside a Rails view template?

You call the helper method directly by its name in the view template. Rails makes helper methods accessible in views automatically.

intermediate

Why should you use view helpers instead of putting logic directly in views?

Using helpers keeps views simple and focused on display. It improves code reuse, readability, and makes testing easier by separating logic from HTML.

beginner

Example: What does this helper method do?

def format_price(price)
  number_to_currency(price)
end

This helper method formats a number as a currency string, like "$12.34", using Rails' built-in number_to_currency helper.

Where are Rails view helpers typically stored?

A app/controllers

B app/models

C app/helpers

D app/views

Rails stores view helper modules inside the app/helpers directory.

What is the main benefit of using view helpers?

A Keep views clean and reusable

B Store database queries

C Handle user authentication

D Manage routing

View helpers keep view templates clean by moving logic out of views.

How do you call a helper method in a Rails view?

A Directly by method name

B Using @helper.method_name

C Using Controller.method_name

D Using JavaScript

Helper methods are available directly by name in views.

Which of these is NOT a good use for a view helper?

A Formatting dates

B Generating HTML snippets

C Creating reusable UI code

D Running database queries

Database queries belong in models or controllers, not helpers.

What Rails helper method formats numbers as currency?

A to_currency

B number_to_currency

C currency_format

D format_currency

Rails provides number_to_currency to format numbers as currency strings.

Explain what view helpers are and why they are useful in Rails.

Think about how to keep your HTML templates simple and readable.

Describe how to create and use a custom view helper method in a Rails app.

Helpers live in a special folder and are ready to use in views.