Tagged Unions

What it does

The tagged-unions skill allows AI agents to understand and generate TypeScript code that utilizes tagged unions. Tagged unions, also known as discriminated unions, are a powerful type system feature in TypeScript enabling more robust and type-safe handling of different data types within a single variable. This skill enables the agent to reason about and produce code leveraging this pattern for improved clarity and error prevention.

When to use it

• Handling Variant Data: When an AI agent needs to process data that can be one of several distinct, typed forms (e.g., success/failure responses from an API).
• Type-Safe State Management: For creating state machines or complex component logic where the type of state changes dynamically.
• Improving Code Readability: When refactoring existing code to make it more understandable and maintainable by leveraging tagged unions for clearer data representation.
• Generating Data Structures: To create custom data structures that represent a union of different types, ensuring type safety during operations.

Key capabilities

• Understanding tagged union syntax in TypeScript.
• Generating code utilizing discriminated unions.
• Reasoning about the benefits of using tagged unions for type safety.
• Applying tagged unions to various scenarios (e.g., API responses, state management).

Example prompts

• "Generate a TypeScript function that handles either a 'Success' or 'Error' result using a tagged union."
• "Show me how to implement a simple state machine in TypeScript with tagged unions."
• “Write a type for an API response which can be either a User object or an ErrorMessage object.”

Tips & gotchas

This skill assumes basic familiarity with TypeScript syntax and concepts. While tagged unions improve type safety, they can increase code complexity if overused; consider the trade-offs when applying this pattern.