What are the differences between generics and union types in TypeScript?

What are the differences between generics and union types in TypeScript?

Generics allow you to create reusable components that can work with any data type, while union types let you specify that a variable can hold multiple types.

Can you give me an example of each?

Sure! A generic example is a function that takes an array of any type: function identity<T>(arg: T): T { return arg; }. A union type example is: let value: string | number; which can hold either a string or a number.

When should I use generics over union types?

Use generics when you want to create a flexible function or class that can handle various types, and use union types when you need to specify a variable that can be one of several specific types.

Are there any performance differences between them?

Generally, there are no significant performance differences. The choice between generics and union types is more about design and type safety than performance.