fp-ts Option and Either Guide

This skill covers practical usage of Option and Either from fp-ts for safer TypeScript code.

When to Use Option vs Either

Use Option when:

• A value may or may not exist (nullable/undefined scenarios)
• You don't need to know WHY a value is missing
• Working with optional fields, array lookups, or dictionary access

Use Either when:

• An operation can fail and you need error information
• Replacing try-catch blocks
• You need to communicate different failure reasons
• Building validation pipelines

Imports