Is Curly still maintained in 2024?

No, Curly is deprecated and no longer actively maintained by Zendesk, with version 4.0.0 being the final release. This means it won't receive updates for security or compatibility with newer Rails versions, so it's not recommended for new projects.

Curly vs ERB: which is better for Rails?

Curly enforces a strict separation of logic into presenter classes, leading to more testable and maintainable templates, but adds overhead. ERB is more flexible and widely supported, allowing inline Ruby but can become messy in complex views. Choose Curly for clean architecture, ERB for simplicity and ecosystem.

How to handle nested collections in Curly templates?

Use collection blocks (e.g., `{{*comments}}`) with nested presenters that automatically receive items and indexes, or context blocks for more control. The README shows defining a `Posts::CommentPresenter` to render each comment within a parent template, forwarding variables like `post` and `comment_counter`.

Can I use Curly with Rails 7 or later?

Possibly, but since Curly is deprecated, compatibility isn't guaranteed. It integrates with Rails helpers and caching, but you might encounter issues with new Rails features or dependencies. Check the GitHub repository for any open issues or forks with updates.

What's the performance impact of using Curly?

Curly adds a layer of abstraction with presenter classes, which might introduce slight overhead compared to raw ERB, but it includes caching optimizations like `cache_key` methods to mitigate this. In practice, performance is similar to other template engines for most Rails applications.

How to migrate an existing ERB app to Curly?

Gradually replace `.erb` files with `.curly` templates and create corresponding presenter classes, moving logic from templates to presenter methods. The README provides a generator (`rails generate curly:install`) to set up layouts, but be prepared for refactoring and testing each view.

Curly — Ruby HTML Template Language

What is Curly?

Curly is a template language for Ruby on Rails that completely separates HTML structure from Ruby logic by moving all presentation logic to presenter classes. It replaces `.erb` files with `.curly` templates, where components like `{{author}}` map to methods in a presenter, ensuring templates remain clean and logic is testable.

Target Audience

Ruby on Rails developers building maintainable web applications who want to avoid mixing Ruby code with HTML in templates. It's particularly useful for teams prioritizing clean separation of concerns in their view layer.

Value Proposition

Developers choose Curly for its strict separation of structure and logic, which leads to more maintainable and testable templates compared to traditional ERB. Its presenter-based approach reduces template complexity and integrates seamlessly with Rails conventions.

The Curly template language allows separating your logic from the structure of your HTML templates.

Use Cases

Best For

Enforcing clean separation between HTML and Ruby logic in Rails views
Building maintainable templates with all logic in testable presenter classes
Replacing ERB templates with a more structured alternative
Implementing caching strategies at the presenter level
Creating reusable widget-style components with context blocks
Integrating I18n or hierarchical data using identifiers like `{{i18n.homepage.header}}`

Not Ideal For

Projects requiring long-term maintenance and updates, as Curly is deprecated and no longer supported by Zendesk
Teams heavily invested in ERB or other templating engines with extensive gem ecosystems and community support
Rapid prototyping where the overhead of creating presenter classes for every template would slow iteration
Applications needing server-side rendering with minimal abstraction, preferring Rails' default ERB for simplicity

Pros & Cons

Pros

Strict Logic Separation

Enforces clean templates by moving all Ruby logic to presenter classes, making HTML declarative and logic unit-testable, as shown in the README's example of moving methods like `author_link` to a presenter.

Rails Native Integration

Seamlessly integrates with Rails helpers, layouts, content blocks, and RSpec testing, allowing use of methods like `link_to` and `content_for` within presenters without extra setup.

Flexible Component System

Supports advanced features like identifiers for hierarchical data (e.g., `{{i18n.homepage.header}}`), attributes for parameterized components, and context blocks for inline widget templates, enabling complex rendering scenarios.

Built-in Caching Control

Provides dynamic and static caching at the presenter level with methods like `cache_key` and `version`, simplifying cache expiration and integration with Rails' caching mechanisms.

Cons

Deprecated and Unmaintained

The project is officially no longer updated by Zendesk, with version 4.0.0 as the final release, posing risks for security, compatibility with future Rails versions, and lack of bug fixes.

Presenter Class Overhead

Requires creating a separate presenter class for every template or partial, which can add boilerplate and complexity for simple views compared to ERB's inline Ruby snippets.

Limited Adoption and Ecosystem

Has a smaller community and fewer third-party extensions compared to ERB or Haml, making it harder to find tutorials, plugins, or support for edge cases.

Syntax Learning Curve

Introduces a custom syntax (e.g., `{{*comments}}` for collections, `{{@component}}` for context blocks) that developers must learn, unlike ERB's more familiar Ruby-embedded approach.

What is Curly?

Target Audience

Value Proposition

Use Cases

Best For

Enforcing clean separation between HTML and Ruby logic in Rails views
Building maintainable templates with all logic in testable presenter classes
Replacing ERB templates with a more structured alternative
Implementing caching strategies at the presenter level
Creating reusable widget-style components with context blocks
Integrating I18n or hierarchical data using identifiers like `{{i18n.homepage.header}}`

Not Ideal For

Projects requiring long-term maintenance and updates, as Curly is deprecated and no longer supported by Zendesk
Teams heavily invested in ERB or other templating engines with extensive gem ecosystems and community support
Rapid prototyping where the overhead of creating presenter classes for every template would slow iteration
Applications needing server-side rendering with minimal abstraction, preferring Rails' default ERB for simplicity

Pros & Cons

Pros

Strict Logic Separation

Rails Native Integration

Seamlessly integrates with Rails helpers, layouts, content blocks, and RSpec testing, allowing use of methods like `link_to` and `content_for` within presenters without extra setup.

Flexible Component System

Built-in Caching Control

Provides dynamic and static caching at the presenter level with methods like `cache_key` and `version`, simplifying cache expiration and integration with Rails' caching mechanisms.

Cons

Deprecated and Unmaintained

The project is officially no longer updated by Zendesk, with version 4.0.0 as the final release, posing risks for security, compatibility with future Rails versions, and lack of bug fixes.

Presenter Class Overhead

Requires creating a separate presenter class for every template or partial, which can add boilerplate and complexity for simple views compared to ERB's inline Ruby snippets.

Limited Adoption and Ecosystem

Has a smaller community and fewer third-party extensions compared to ERB or Haml, making it harder to find tutorials, plugins, or support for edge cases.

Syntax Learning Curve

Introduces a custom syntax (e.g., `{{*comments}}` for collections, `{{@component}}` for context blocks) that developers must learn, unlike ERB's more familiar Ruby-embedded approach.

Curly

What is Curly?

Overview

Use Cases

Best For

Not Ideal For

Pros & Cons

Pros

Cons

Frequently Asked Questions

Related Projects

Found a gem we're missing?

Curly

What is Curly?

Overview

Use Cases

Best For

Not Ideal For

Pros & Cons

Pros

Cons

Frequently Asked Questions

Related Projects

Found a gem we're missing?