es-toolkit
Version:
A state-of-the-art, high-performance JavaScript utility library with a small bundle size and strong type annotations.
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text/typescript
type GetFieldTypeOfArrayLikeByKey<T extends unknown[], K> = K extends number ? T[K] : K extends `${infer N extends number}` ? T[N] : K extends keyof T ? T[K] : undefined;
type GetFieldTypeOfStringByKey<T extends string, K> = K extends number ? T[K] : K extends `${infer N extends number}` ? T[N] : K extends keyof T ? T[K] : undefined;
type GetFieldTypeOfNarrowedByKey<T, K> = T extends unknown[] ? GetFieldTypeOfArrayLikeByKey<T, K> : T extends string ? GetFieldTypeOfStringByKey<T, K> : K extends keyof T ? T[K] : K extends number ? `${K}` extends keyof T ? T[`${K}`] : undefined : K extends `${infer N extends number}` ? N extends keyof T ? T[N] : undefined : undefined;
type GetFieldTypeOfNarrowedByDotPath<T, P> = P extends `${infer L}.${infer R}` ? GetFieldType<GetFieldTypeOfNarrowedByKey<T, L>, R, 'DotPath'> : GetFieldTypeOfNarrowedByKey<T, P>;
type GetFieldTypeOfNarrowedByLcKR<T, Lc, K, R> = '' extends R ? GetFieldType<GetFieldTypeOfNarrowedByDotPath<T, Lc>, K, 'Key'> : R extends `.${infer Rc}` ? GetFieldType<GetFieldType<GetFieldTypeOfNarrowedByDotPath<T, Lc>, K, 'Key'>, Rc> : GetFieldType<GetFieldType<GetFieldTypeOfNarrowedByDotPath<T, Lc>, K, 'Key'>, R>;
type GetFieldTypeOfNarrowedByLKR<T, L, K, R> = '' extends L ? '' extends R ? GetFieldTypeOfNarrowedByKey<T, K> : R extends `.${infer Rc}` ? GetFieldType<GetFieldTypeOfNarrowedByKey<T, K>, Rc> : GetFieldType<GetFieldTypeOfNarrowedByKey<T, K>, R> : L extends `${infer Lc}.` ? GetFieldTypeOfNarrowedByLcKR<T, Lc, K, R> : GetFieldTypeOfNarrowedByLcKR<T, L, K, R>;
type GetFieldTypeOfNarrowed<T, X, XT extends 'DotPath' | 'Key' | 'Path'> = XT extends 'Key' ? GetFieldTypeOfNarrowedByKey<T, X> : XT extends 'DotPath' ? GetFieldTypeOfNarrowedByDotPath<T, X> : X extends `${infer L}['${infer K}']${infer R}` ? GetFieldTypeOfNarrowedByLKR<T, L, K, R> : X extends `${infer L}["${infer K}"]${infer R}` ? GetFieldTypeOfNarrowedByLKR<T, L, K, R> : X extends `${infer L}[${infer K}]${infer R}` ? GetFieldTypeOfNarrowedByLKR<T, L, K, R> : GetFieldTypeOfNarrowedByDotPath<T, X>;
type GetFieldTypeOfObject<T, X, XT extends 'DotPath' | 'Key' | 'Path'> = Extract<T, unknown[]> extends never ? GetFieldTypeOfNarrowed<T, X, XT> : GetFieldTypeOfNarrowed<Exclude<T, unknown[]>, X, XT> | GetFieldTypeOfNarrowed<Extract<T, unknown[]>, X, XT>;
type GetFieldTypeOfPrimitive<T, X, XT extends 'DotPath' | 'Key' | 'Path'> = Extract<T, string> extends never ? T extends never ? never : undefined : (Exclude<T, string> extends never ? never : undefined) | GetFieldTypeOfNarrowed<Extract<T, string>, X, XT>;
type GetFieldType<T, X, XT extends 'DotPath' | 'Key' | 'Path' = 'Path'> = Extract<T, object> extends never ? GetFieldTypeOfPrimitive<T, X, XT> : GetFieldTypeOfPrimitive<Exclude<T, object>, X, XT> | GetFieldTypeOfObject<Extract<T, object>, X, XT>;
export type { GetFieldType };