Comparative analysis of the main frameworks - Django, Ruby on Rails, Laravel, and Express.js

Performance:
◾ Django is known for its efficiency and speed due to the built-in optimisations and the use of the Python programming language.
◾ Rails also provides high performance, especially for developing web applications with a large number of standard features.
◾ Laravel has quite good performance because it is built on top of PHP and uses caching.
◾ As a Node.js framework, Express.js performance depends on the efficient use of JavaScript and asynchronous operations.

Scalability:
◾ Django can scale effectively for large projects due to its structure and support for asynchronous operations.
◾ Rails also has scalability, but some developers note that it may require more resources than other frameworks.
◾ Laravel has quite good scalability with the ability to use various packages and extensions.
◾ Express.js is very flexible and can be scaled for large and complex applications due to its asynchronous nature and support for Node.js.

Documentation and support:
◾ Django has well-structured and detailed documentation that facilitates quick learning and project development. In addition, Django has long-term support and regular updates.
◾ Rails is also known for its well-written documentation, which makes the development process easier. Support for Rails can be less stable than other frameworks because it is usually updated quickly.
◾ Laravel provides clear and easy-to-understand documentation that helps you learn the framework quickly. Its community is also actively supported, which allows you to develop projects on a long-term basis.
◾ Express.js has detailed documentation that helps developers get started with the framework quickly. Since it is a Node.js framework, its support and updates depend on the activity of the Node.js community.

Extensibility and flexibility:
◾ Django provides built-in authentication, an administrative dashboard, and other standard features that make it attractive for getting started quickly.
◾ However, there are many third-party packages that allow you to extend the framework's capabilities as needed.
◾ Rails is famous for its Convention over Configuration, which allows you to develop applications quickly. It also has a wide range of extensions and gems that allow you to extend the functionality.
◾ Laravel is known for its flexibility and ease of customisation. It has a large number of extensions (packages) through Composer, which makes it easy to extend functionality.
◾ Express.js is a minimalist framework that provides basic functions for building web servers using Node.js. Its flexibility lies in the fact that it allows developers to build applications according to their needs using various Node.js modules and libraries.

These aspects can be crucial when choosing a framework for your project depending on its needs and requirements.