What this snippet does
TypeScript automatically flattens nested Promises, so awaiting an async function returning a Promise resolves to the inner value.
Expected output
val
Why practise typing this
Typing async & promises code builds muscle memory for the symbols and indentation TypeScript uses most, which prose-based typing tests never cover. DevType measures your words per minute and accuracy on this snippet and tracks the individual characters you mistype, so later lessons can target them.
More TypeScript practice
- Defining a function returning a typed PromiseAsync & Promises · intermediate
- Fetching user data with typed async/awaitAsync & Promises · intermediate
- Forgetting to await a PromiseAsync & Promises · intermediate
- Awaited type behavior in async functionsAsync & Promises · intermediate
- Rejecting a Promise with an untyped errorAsync & Promises · intermediate
- Typing Promise.all with mixed typesAsync & Promises · intermediate