All 10 Error Handling questions
More in Error Handling
How does a try/catch block work? What's the difference between a built-in Error and throwing a plain string or object? How do you create a custom error class? How do you catch errors from a Promise chain versus async/await? What is error propagation, and how does an uncaught error in a nested function behave? What is the Error cause option and what problem does it solve? How do global error handlers like window.onerror and unhandledrejection work? Why can errors thrown inside a setTimeout callback NOT be caught by a surrounding try/catch? How do you implement a retry-with-backoff pattern around a function that might throw?
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JavaScript › Error Handling

What does the finally block do?

Beginner

Answer

finally always runs after try/catch, whether or not an error was thrown or caught, and even if the try block returns early — making it ideal for cleanup code that must always execute.
function readFile() {
  openFile();
  try {
    return process();
  } finally {
    closeFile(); // always runs
  }
}
Real-world example Ensuring a loading spinner is hidden whether an API call succeeds or fails.

Common follow-ups: Does a return inside finally override a return from try?

Async Iterators & Streams
All 10 Error Handling questions