When choosing a templating engine for a Node.js application, it's important to understand how different engines compare in terms of features, syntax, and use cases. Here's a comparison of EJS (Embedded JavaScript) with other popular templating engines like Pug (formerly Jade), Handlebars, and Mustache:

1. EJS (Embedded JavaScript)

Features:

• Syntax: Uses <% %> delimiters for embedding JavaScript logic and <%= %> for outputting values.
• Data Binding: Supports passing data from the server to templates.
• Template Inheritance: Limited template inheritance; does not support built-in support for layouts or extends like Pug.
• Partials: Allows including partial templates using <%- include('partial') %>.
• JavaScript Logic: Allows using JavaScript directly within templates.
• Safe HTML Output: Supports raw HTML rendering with <%- %>.

Pros:

• Simple Syntax: Easy to learn and use for those familiar with HTML and JavaScript.
• Flexibility: Directly embeds JavaScript, making it highly flexible.
• Integration with Express: Seamless integration with Express.js.

Cons:

• Limited Features: Lacks built-in features for template inheritance and more advanced template management compared to some other engines.

2. Pug (formerly Jade)

Features:

• Syntax: Uses indentation-based syntax without explicit closing tags, making it more concise.
• Data Binding: Supports passing data to templates.
• Template Inheritance: Strong support for template inheritance with extends and block.
• Partials: Includes partials with include and extends for layouts.
• JavaScript Logic: Supports JavaScript expressions and logic.

Pros:

• Concise Syntax: Less verbose, using indentation instead of explicit tags.
• Template Inheritance: Strong support for inheritance and layout management.
• Readability: Can improve readability and maintainability with its indentation-based approach.

Cons:

• Learning Curve: May have a steeper learning curve for those accustomed to HTML-like syntax.
• Debugging: Indentation-based syntax can make debugging more challenging.

3. Handlebars

Features:

• Syntax: Uses {{ }} for expressions and helpers.
• Data Binding: Supports passing data to templates.
• Template Inheritance: Supports partials and helpers but does not have built-in template inheritance like Pug.
• Partials: Allows including partial templates using {{> partial}}.
• JavaScript Logic: Limited JavaScript logic; encourages the use of helpers for complex logic.

Pros:

• Logic-less Templates: Encourages separation of logic from templates, making templates easier to maintain.
• Helpers: Provides a robust system for creating reusable helper functions.
• Widely Used: Popular choice with a large ecosystem of helpers and extensions.

Cons:

• Limited Logic: Less flexible in terms of embedding complex logic compared to EJS.
• Learning Curve: Requires understanding of Handlebars-specific syntax and concepts.

4. Mustache

Features:

• Syntax: Uses {{ }} for expressions and supports simple logic.
• Data Binding: Supports passing data to templates.
• Template Inheritance: Does not support template inheritance natively but allows for partials.
• Partials: Allows including partials using {{> partial}}.
• JavaScript Logic: Limited to basic logic and conditionals; encourages minimal logic within templates.

Pros:

• Simplicity: Very simple and lightweight, with a focus on minimalism.
• Logic-less: Promotes the separation of logic from templates.

Cons:

• Limited Features: Lacks advanced features like template inheritance and complex logic.
• Less Flexible: Not as flexible as EJS or Handlebars for embedding complex JavaScript.

Summary of Comparison

• EJS:

  • Strengths: Simple syntax, direct JavaScript integration, flexible.
  • Weaknesses: Limited template inheritance, more verbose compared to some alternatives.

• Pug:

  • Strengths: Concise syntax, strong template inheritance, readable.
  • Weaknesses: Steeper learning curve, debugging challenges due to indentation-based syntax.

• Handlebars:

  • Strengths: Logic-less templates, robust helper system, widely used.
  • Weaknesses: Limited JavaScript logic within templates, requires learning Handlebars-specific syntax.

• Mustache:

  • Strengths: Very simple and lightweight, promotes separation of logic.
  • Weaknesses: Limited features, minimal logic support.