Jinja2 vs Nunjucks: What are the differences?

Introduction

Jinja2 and Nunjucks are both template engines for JavaScript and Python, but they have some key differences. This article will highlight and explain six main differences between Jinja2 and Nunjucks.

1. Template Inheritance:

Jinja2 supports template inheritance, which allows the creation of a base template with the common layout, and then extending it to add specific content in child templates. This feature helps to reduce code duplication and promote reusability. On the other hand, Nunjucks lacks built-in support for template inheritance, making it less flexible for creating structured templates.

2. Syntax Variations:

While both engines are inspired by the Django template language, they have syntax variations. Jinja2 uses double curly braces for variable interpolation and block tags, whereas Nunjucks uses a combination of curly braces and percentage signs. This difference in syntax can be challenging when switching between the two engines.

3. Autoescape Behavior:

One significant difference between Jinja2 and Nunjucks is how they handle autoescaping. In Jinja2, autoescape is disabled by default, meaning that variables are not automatically escaped when rendered. In contrast, Nunjucks automatically escapes all variables by default, providing a higher level of security against Cross-Site Scripting (XSS) attacks. However, this feature can sometimes lead to unexpected behavior and the need for manual escaping in certain scenarios.

4. Custom Filters and Functions:

Jinja2 allows developers to create and register custom filters and functions, extending the template engine's capabilities and making it more versatile. Nunjucks, on the other hand, does not provide built-in support for custom filters and functions. This limitation can be a drawback when advanced logic or complex transformations are needed within templates.

5. JavaScript and Python Support:

One of the key differences between Jinja2 and Nunjucks is the programming languages they primarily support. Jinja2 is designed for Python applications, while Nunjucks is tailored for JavaScript environments. This distinction affects how the template engines integrate with their respective ecosystems and determines the available range of features and libraries.

6. Template Execution Environment:

Nunjucks provides a sandboxed environment for template execution, which restricts access to potentially unsafe or server-related objects, providing an additional layer of security. Jinja2, on the other hand, does not offer a built-in sandboxed environment. This aspect makes Nunjucks a preferred choice when working in environments where security is a top priority.

In Summary, Jinja2 and Nunjucks differ in terms of template inheritance, syntax variations, autoescape behavior, custom filters and functions support, programming language focus, and template execution environment.