What?

This PR introduces two new TypeScript helper types, AsyncAction<ReturnType> and TypeYield<T>, to the Interactivity API.

It also adds documentation for both helpers in the "Using TypeScript" guide, explaining their purpose and how to use them to solve common typing issues with asynchronous actions (generators).

Props to @luisherranz.

Why?

When working with asynchronous actions (defined as generators) in the Interactivity API and TypeScript, developers can encounter two main issues:

1. Circular References: If state is used within a yield expression or if the generator's return value depends on state, TypeScript can struggle to infer types, leading to circular reference errors or types defaulting to any.
2. Typing Yielded Values: Even if the overall generator type is correctly inferred or specified, the actual value resolved by an individual yield expression (e.g., the result of a fetched promise) is not accurately typed within the generator's scope, defaulting to any.

How?

• AsyncAction<ReturnType>: Defined as Generator<any, ReturnType, unknown>.

  This helper allows developers to explicitly type the return value of an asynchronous action (generator). By using any for the yielded values, it helps break circular type dependencies when state is used within yield expressions or in the final return value.

• TypeYield<T extends (...args: any[]) => Promise<any>>: Defined as Awaited<ReturnType<T>>.

  This helper allows developers to explicitly type the value that a yield expression resolves to, by providing the type of the async function/operation being yielded.