@thi.ng/api/path.d.ts

import type { Keys, Keys1, Keys2, Keys3, Keys4, Keys5, Keys6, Keys7, ValN } from "./keyval.js";
import type { Maybe } from "./null.js";
import type { NumOrString } from "./prim.js";
import type { Head, IsEmpty, Tail } from "./tuple.js";
/**
 * Unchecked lookup path for nested data structures.
 */
export type Path = readonly NumOrString[] | NumOrString;
/**
 * Empty lookup path.
 */
export type Path0 = readonly [];
/**
 * Type checked lookup path (depth 1)
 */
export type Path1<T, A> = A extends Keys<T> ? readonly [A] : never;
/**
 * Type checked lookup path (depth 2)
 */
export type Path2<T, A, B> = A extends Keys<T> ? B extends Keys1<T, A> ? readonly [A, B] : never : never;
/**
 * Type checked lookup path (depth 3)
 */
export type Path3<T, A, B, C> = A extends Keys<T> ? B extends Keys1<T, A> ? C extends Keys2<T, A, B> ? readonly [A, B, C] : never : never : never;
/**
 * Type checked lookup path (depth 4)
 */
export type Path4<T, A, B, C, D> = A extends Keys<T> ? B extends Keys1<T, A> ? C extends Keys2<T, A, B> ? D extends Keys3<T, A, B, C> ? readonly [A, B, C, D] : never : never : never : never;
/**
 * Type checked lookup path (depth 5)
 */
export type Path5<T, A, B, C, D, E> = A extends Keys<T> ? B extends Keys1<T, A> ? C extends Keys2<T, A, B> ? D extends Keys3<T, A, B, C> ? E extends Keys4<T, A, B, C, D> ? readonly [A, B, C, D, E] : never : never : never : never : never;
/**
 * Type checked lookup path (depth 6)
 */
export type Path6<T, A, B, C, D, E, F> = A extends Keys<T> ? B extends Keys1<T, A> ? C extends Keys2<T, A, B> ? D extends Keys3<T, A, B, C> ? E extends Keys4<T, A, B, C, D> ? F extends Keys5<T, A, B, C, D, E> ? readonly [A, B, C, D, E, F] : never : never : never : never : never : never;
/**
 * Type checked lookup path (depth 7)
 */
export type Path7<T, A, B, C, D, E, F, G> = A extends Keys<T> ? B extends Keys1<T, A> ? C extends Keys2<T, A, B> ? D extends Keys3<T, A, B, C> ? E extends Keys4<T, A, B, C, D> ? F extends Keys5<T, A, B, C, D, E> ? G extends Keys6<T, A, B, C, D, E, F> ? readonly [A, B, C, D, E, F, G] : never : never : never : never : never : never : never;
/**
 * Type checked lookup path (depth 8)
 */
export type Path8<T, A, B, C, D, E, F, G, H> = A extends Keys<T> ? B extends Keys1<T, A> ? C extends Keys2<T, A, B> ? D extends Keys3<T, A, B, C> ? E extends Keys4<T, A, B, C, D> ? F extends Keys5<T, A, B, C, D, E> ? G extends Keys6<T, A, B, C, D, E, F> ? H extends Keys7<T, A, B, C, D, E, F, G> ? readonly [A, B, C, D, E, F, G, H] : never : never : never : never : never : never : never : never;
/**
 * Semi-typechecked lookup path (depth > 8). Only the first 8 levels are
 * checked.
 */
export type DeepPath<T, A, B, C, D, E, F, G, H> = A extends Keys<T> ? B extends Keys1<T, A> ? C extends Keys2<T, A, B> ? D extends Keys3<T, A, B, C> ? E extends Keys4<T, A, B, C, D> ? F extends Keys5<T, A, B, C, D, E> ? G extends Keys6<T, A, B, C, D, E, F> ? H extends Keys7<T, A, B, C, D, E, F, G> ? readonly [A, B, C, D, E, F, G, H, ...NumOrString[]] : never : never : never : never : never : never : never : never;
/**
 * Returns `RES` if `PRED` is `never`, else `Maybe<RES>`
 */
export type OptVal<PRED, RES> = [PRED] extends [never] ? RES : Maybe<RES>;
/**
 * Returns true if `T` includes undefined.
 */
export type IsOpt<T> = T extends undefined ? true : never;
/**
 * Internal recursive helper type for {@link IsOptPath}.
 */
type IsOptR<T, K, P extends unknown[]> = K extends Keys<T> ? [true] extends [IsOpt<T[K]>] ? true : {
    0: IsOptR<Required<T>[K], Head<P>, Tail<P>>;
    1: never;
}[IsEmpty<P>] : never;
/**
 * Returns true if given path contains any intermediate properties
 * declared as optional in type `T`.
 *
 * Reference:
 * https://stackoverflow.com/q/60869412/294515
 */
export type IsOptPath<T, P extends unknown[]> = P extends [] ? never : IsOptR<T, Head<P>, Tail<P>>;
/**
 * Similar to {@link PathVal}, but also takes into account if given path
 * contains any intermediate properties declared as optional in type
 * `T`. If that's the case, returns union of `undefined` and inferred
 * value for path, else just the latter.
 *
 * Context & reference: https://stackoverflow.com/q/60869412/294515
 */
export type OptPathVal<T, P extends unknown[]> = OptVal<IsOptPath<T, P>, ValN<T, P>>;
/**
 * Returns nested value type for given path into `T` or `never` if path
 * is incompatible with `T`.
 */
export type PathVal<T, P extends unknown[]> = ValN<T, P>;
export {};
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