Split code

[Katsyuta]

#2

Problems:

1. Violanse SRP:
   The NodeTranslator class has multiple responsibilities. It manages several states and includes many methods for different logic, which makes the class difficult to maintain. As a result, the overall logic of the class is hard to understand and make changes.

The some responsible:

• Observing the intersection of DOM elements with the visible part of the screen for implementing lazy translation.
• Setting up handlers to process DOM mutation (translation of added and updated nodes)
• Managing the translation of DOM elements (the logic for handlig tree of elements, methods for add, update and delete nodes, keeping node storage)

Solution: Split the class into multiple entities:

• The LazyTranslator class: Translate element when it intersect viewport.
• The NodesTranslator class: Manages the translation of DOM nodes, prvide method for add, update and etc.
• The DomTranslator class: Sets handlers for DOM mutations and creates the necessary dependencies.

Profit:
After this, each class will have a single responsibility and will be easier to maintain. We can add new logic without complicating the class NodeTranslator. Example, LazyTranslator can be used outside the project or we easy can replace implimentation.

2. Tightly coupled code
   The methods are directly connected to each other. This lack of flexibility makes the code tightly coupled, meaning that changes in one part require changes in another part.
   If the logic for lazy translation changes, the code that relies on it must also be modified, as the methods are directly dependent on each other, or if we change the logic for storing nodes, we should update the code that uses node storage

This may make changes harder to implement, take more time, increase the likelihood of errors, and reduce the willingness to modify the code.

Solution: Split code as in the previous proposal aand pass all dependencies through the constructor.

• The LazyTranslator class receives a callback for translating nodes in the constructor. This allows the class to be used independently of the rest of the code.
• The NodesTranslator class receives the LazyTranslator instance in the constructor and uses its methods. This allows any implementation of LazyTranslator to be provided.
• The DomTranslation class creates the necessary dependencies and use the methods from NodesTranslator for setting mutation handlers.

Profit:
After these changes, the classes are no longer tightly coupled and can be modified independently.

After all the changes, we have a few classes that can be replaced or updated independently, and each class is easier to understand.

[vitonsky]

• Explain what exactly problem we have and what changes needed
• Refactor all code, since it is not clear why we need current changes
• Explain changes in this PR. Elaborate why new entities has been introduced
• Add tests to cover all changes. Add unit tests + integration tests that would reproduce real world interactions of user with DOM

[Katsyuta]

@vitonsky can you repeat the review?

Key changes:
Several classes have been created:

• The LazyTranslator class: Translates an element when it intersects with the viewport.
• The NodesTranslator class: Manages the translation of DOM nodes, providing methods for adding, updating, etc.
• The DomTranslator class: Sets handlers for DOM mutations and creates the necessary dependencies.

Unit tests have been added for the LazyTranslator and NodesTranslator classes, as well as a test for their combined functionality.

[vitonsky]

I close this PR since there are no reasons to make changes in description.
I see only generic "problems" from wikipedia, but not specific code lines mentions and its problems demonstration.

Also as i see this PR have breaking changes:

• it broke a public API, so we have to up major version + users must update code usage
• tests have been changed, snapshots has been deleted, so it is not possible to verify that after this changes code works fine as before

If you still see problems in code, please file the issue with explanation of specific problems and your plan how to fix them. Thank you