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Scala for Backend Engineering & Functional Programming · Lesson

Error Handling in IO

handleError.

Errors as Values

In Cats Effect, an IO can fail. The failure is part of the value, so you can inspect and recover from it without unstructured try/catch.

Raising Errors

Use IO.raiseError to create a failed IO explicitly with a chosen exception.

import cats.effect.IO

val failed: IO[Int] =
  IO.raiseError(new RuntimeException("boom"))

All lessons in this course

  1. Cats Type Classes
  2. The IO Monad
  3. Composing IO
  4. Error Handling in IO
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