No, Single-File Component doesn’t violate the principle of Separation of Concerns: Separation of concerns is not equal to the separation of file types. The ultimate goal of engineering principles is to improve the maintainability of codebases. Separation of concerns, when applied dogmatically as separation of file types, does not help us reach that goal in the context of increasingly complex frontend applications.
In modern UI development, we have found that instead of dividing the codebase into three huge layers that interweave with one another, it makes much more sense to divide them into loosely-coupled components and compose them. Inside a component, its template, logic, and styles are inherently coupled, and colocating them actually makes the component more cohesive and maintainable.
Note even if you don’t like the idea of Single-File Components, you can still leverage its hot-reloading and pre-compilation features by separating your JavaScript and CSS into separate files using Src Imports.
