infer ana amfani da shi a cikin conditional type don karɓa (fitar) nau'i daga cikin wata nau'i zuwa sabuwar nau'i mai suna (type variable) da za ka iya amfani da shi. Ita ce pattern-matching para nau'aye.
<T> = T (infer U)[] ? U : ;
A = <[]>;
B = <[]>;
Ka karanta shi kamar: "idan T ya dace da tsarin U[], ɗaura U ga duk abin da nau'i-nau'in kashi shine, kuma mayar da shi." infer U yana bayyana wuri mai tucani mai tucani da compiler ke cike shi ta hanyar dace.
// the resolved type of a Promise
type Awaited2<T> = T extends Promise<infer R> ? R : T;
type R = Awaited2<Promise<User>>; // User
// a function's return type (this is how ReturnType is built)
type MyReturn<T> = T extends (...args: any[]) => infer R ? R : never;
type X = MyReturn<() => number>; // number
// a function's first parameter
type FirstArg<T> = T extends (a: infer A, ...rest: any[]) => any ? A : never;
type UnwrapBoth<T> =
T extends Promise<infer U> ? UnwrapBoth<U> : // recurse to unwrap nested promises
T extends (infer E)[] ? E : T;
Ka iya amfani da mahimman infers a cikin tsari gida kuma ma da makaiya.
infer shine injin a bayan nau'i-nau'i na jiji kamar ReturnType, Parameters, Awaited, da InstanceType, da a bayan abin da malam nawa ke samu hula cewa yadda ake fitar nau'i-nau'i daga fetchers ko prop daga component.
Ya ba wa nau'i-nau'i nau'i "bubuwa" wajen hadad nau'i mai tsauri kuma ja ɓoye sasannin - kayan kakasu mafi karfi don rubutu nau'i-nau'i wajen dace da sauran nau'i-nau'i.