What are some use cases of template literal types in TypeScript?

Template literal types in TypeScript offer a versatile way to manipulate and use string types more dynamically within the type system. Introduced in TypeScript 4.1, these types allow developers to construct new string types from existing ones, providing powerful capabilities for type checking and inference. Here are some practical use cases of template literal types in TypeScript:

1. Generating Dynamic String Types

Template literal types can be used to generate dynamic string types based on conditions or inputs. For example, you can define a type that represents different CSS class names based on input variables, ensuring type safety when generating class names dynamically.

2. Type-Safe API Endpoints

Developers can use template literal types to construct type-safe API endpoint strings. By combining literals and embedded expressions, you can ensure that only valid endpoint strings are used within your application. For instance, you could define types for specific API paths, and any deviation from these paths would be caught at compile time[2].

3. Conditional Types and Inference

Template literal types work well with conditional types to perform more complex type manipulations. For example, you can infer parts of a string and use these inferences to define other types. This is particularly useful in scenarios where you need to unpack or transform types based on certain patterns or conditions[1].

4. Enhancing Function Typing

You can use template literal types to enhance the typing of functions by dynamically generating expected parameter types or return types. For instance, a function that handles events might use template literal types to strictly type the event names it can accept, such as "click" or "hover", combined with specific actions[5].

5. Mapping and Remapping Keys in Types

Template literal types can be used in mapped types to dynamically create or modify keys in object types. This is useful for creating types where the keys depend on the values of other properties or external conditions. TypeScript 4.1's introduction of key ...