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Inconsistent type inferring behavior #53776
Description
Bug Report
Hi, we're having issues using inline call of the generic function decorator in a specific context. Unfortunately, I couldn't find anything related to this on stackoverflow, or here. Please check out the code below and feel free to let me know if more information/context is needed. Thanks!
🔎 Search Terms
infer genericinfer generic function
🕗 Version & Regression Information
This is the behavior in every version I tried, and I reviewed the FAQ for entries about inference and generics
⏯ Playground Link
Playground link with relevant code
💻 Code
function deferQuery<TData>({}: {
queryFn: () => Promise<TData>;
onSuccess: (data: TData) => void;
}) {
// ...
}
export function decorate<TParams extends unknown[], TResult>(
func: (...params: TParams) => Promise<TResult>,
...params: TParams
): () => Promise<TResult> {
return () => {
// ...
return func(...params);
};
}
type ArbitraryData = {
property: string;
};
export function getArbitraryData(_id: number): Promise<ArbitraryData[]> {
return Promise.resolve([{property: '123'}]);
}
deferQuery({
queryFn: decorate(getArbitraryData, 10),
onSuccess(data) {
// ^? (parameter) data: unknown
data.forEach(console.log);
},
});
const getData = decorate(getArbitraryData, 10);
deferQuery({
queryFn: getData,
onSuccess(data) {
// ^? (parameter) data: ArbitraryData[]
data.forEach(console.log);
},
});🙁 Actual behavior
data is typed as ArbitraryData[] only when the decorated method is stored in a variable.
🙂 Expected behavior
data is typed as ArbitraryData[] in both cases.
deferQuery({
queryFn: decorate(getArbitraryData, 10),
onSuccess(data) {
// ^? (parameter) data: ArbitraryData[]
data.forEach(console.log);
},
});
const getData = decorate(getArbitraryData, 10);
deferQuery({
queryFn: getData,
onSuccess(data) {
// ^? (parameter) data: ArbitraryData[]
data.forEach(console.log);
},
});
Activity
RyanCavanaugh commentedon Apr 14, 2023
See #47599
chernodub commentedon Apr 14, 2023
Thanks for pointing this out Ryan Cavanaugh (@RyanCavanaugh)! I'm closing this issue.