pattern-matching

Exhaustive, type-safe pattern matching for discriminated unions in TypeScript is achieved using Effect's Data.TaggedEnum and the $match helper to enforce compiler-checked branches across all variants. This approach replaces manual switch statements with declarative, pipeline-friendly patterns.

Yes, Effect Data.TaggedEnum supports nested matches and multi-variant type refinement using the $match and $is helpers. This allows developers to declaratively refine types across complex ADT variants while maintaining compiler-checked exhaustiveness.

The best way to handle state machine variants like Disconnected or Connecting is by defining a TaggedEnum-based union and applying the $match helper with handlers for each state. This ensures declarative, exhaustive type safety across all domain states.

Compiler-checked exhaustiveness for domain events is enforced by defining events with Data.TaggedEnum and using $match to handle every variant. The TypeScript compiler will raise an error if any union variant is missing from the match pattern.

Yes, you can use $match pipelines for result types in Effect without losing type safety. The $match helper integrates into declarative pipelines to refine types securely, ensuring that all possible result variants are matched exhaustively.

A discriminated union match fails to catch missing variants when not using exhaustive helpers like Effect's $match. By defining unions with Data.TaggedEnum and applying $match, the compiler is forced to verify that every variant has a corresponding handler.