scala-functional-error-handling

name	scala-functional-error-handling
description	Handling absence of values and errors in Scala using Option, Try, and Either instead of nulls and exceptions.

Scala discourages the use of null and exception throwing for control flow, preferring functional error handling types from the standard library.

1. Handling Missing Values (Option)

Instead of returning None as in Python, Scala methods should return Option[T].

Python:

def get_metadata(self) -> dict | None:
    return self.metadata if self.metadata else None

Scala:

def getMetadata: Option[Map[String, String]] = {
  if (metadata.nonEmpty) Some(metadata) else None
}

2. Handling Exceptions (Try)

When parsing data (like numbers or dates), Python uses try...except. Scala uses scala.util.Try, which can be easily mapped to an Option if you only care about success/failure.

Python:

def parse_number(text: str) -> float | None:
    try:
        return float(text)
    except ValueError:
        return None

Scala:

import scala.util.Try

def parseNumber(text: String): Option[Double] = {
  Try(text.toDouble).toOption
}

3. Collection Safety

When operating on collections, avoid operations that can throw exceptions (like .head). Use safe alternatives (like .headOption).