Question 1

How to use union-type with React for state management?

Accepted Answer

Define a union type for state variants like loading, success, and error, then use the `case` method in React components to pattern match and render accordingly. For example, create a `State` type and call `state.case({...})` in your component to handle different states exhaustively, ensuring type safety without external libraries.

Question 2

Can I disable type checking in union-type for production?

Accepted Answer

Yes, set `Type.check = false` to disable runtime validation, as mentioned in the README. This improves performance but requires thorough testing since errors won't be caught at runtime, so use it only after development is stable.

Question 3

What are some real-world examples of union-type in use?

Accepted Answer

It's commonly used in functional JavaScript projects for modeling domain data, such as parsers with token types, state machines for UI flows, or error handling with Result types. The README includes examples like `Shape` for geometry and `List` for recursive structures, which can be adapted to real applications.

Question 4

How to handle errors or validation with union-type?

Accepted Answer

Define a union type like `Result` with `Ok` and `Err` variants carrying data, then use pattern matching with `case` to handle successes and errors. For validation, attach validator functions in the type definition to ensure field integrity, and extract fields safely in case handlers.

Question 5

union-type vs TypeScript: which is better for union types in JavaScript?

Accepted Answer

union-type provides runtime validation and pattern matching in plain JavaScript, making it ideal for projects without TypeScript. TypeScript offers compile-time type checking and better IDE integration, so if static typing is a priority, TypeScript's native union types might be more suitable, though union-type adds runtime safety.

Question 6

Is union-type compatible with Node.js and modern bundlers?

Accepted Answer

Yes, it's a plain JavaScript library with no dependencies, so it works seamlessly with Node.js and bundlers like Webpack or Rollup. Simply import it using CommonJS or ES modules, and ensure your environment supports the JavaScript features used, such as arrow functions or destructuring.

union-type

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