What is the best way to handle file uploads?

You should absolutely implement a dedicated service layer to handle multipart requests rather than cluttering your UI components. This separation of concerns is essential for creating testable, injectable modules that can be verified independently of the view layer.

I remember back in 2018 when our team tried to manage multipart streams directly inside a React component. It turned into a nightmare during our regression phase because we couldn't easily mock the file stream for unit tests without hitting the DOM directly.

We ended up refactoring everything into a standalone class that exposed an observable progress stream. Since then, I have always pushed to isolate the transport logic from the presentation layer to ensure that the orchestration of the upload remains predictable and traceable throughout the integration lifecycle.

Handling uploads inside your components is a classic trap that leads to brittle code you will eventually regret. A dedicated service layer is better when you want to unit test the upload lifecycle without spinning up a full UI framework, but direct component handling is acceptable if you are just prototyping and want to save time. Ultimately, the service approach wins for maintainability as soon as your project grows beyond a single developer.

Stop trying to force the upload logic into your components unless you enjoy debugging side effects. You should build a service class that manages the XMLHttpRequest or Fetch lifecycle; it keeps your code clean and allows you to test the logic with simple Jest spies.

Achieving a testable architecture for file uploads necessitates a structural shift toward service-based abstractions. When you bind the upload request directly to the component, you couple your UI lifecycle to the volatility of network-bound asynchronous tasks, which makes unit testing incredibly difficult to stabilize.

By abstracting the logic into a dedicated service, you can inject dependencies such as a mock network handler. This allows you to verify the progress tracking, error handling, and request headers independently. You essentially treat the upload process as a state machine where the UI simply subscribes to status updates. Whether you use a specific library or native implementation, the key is ensuring that the component remains responsible only for rendering the state passed to it by the service. If you keep the upload logic encapsulated in a service, you gain the ability to simulate high-latency or interrupted connections during test execution, which is vital for enterprise-grade software stability. In my experience, attempting to manage multipart boundaries inside a component usually leads to complex state race conditions that are nearly impossible to reproduce in a CI/CD environment. A modular approach resolves these observability gaps by providing a single point of failure that can be instrumented with proper logging and telemetry hooks. Prioritizing this architectural boundary will save you significant technical debt when you eventually need to implement retry logic or chunked uploads.