hkt-toolbelt/type/infer.d.ts

Functional and composable type utilities

import { Kind, Type, Function } from '..';
type _$inferred = string | number | boolean | undefined | null | Function.Function | Kind.Kind | _$inferredTuple | {
    [key: string]: _$inferred;
};
type _$inferredTuple = _$inferred[] | ReadonlyArray<_$inferred>;
/**
 * `_$infer` is a type-level function that infers the most specific type of a value.
 *
 * @template X - The value to infer the type of.
 *
 * @example
 * type T0 = _$infer<'foo'> // 'foo'
 */
export type _$infer<X, Narrow = Type._$cast<X, _$inferred> | [...Type._$cast<X, _$inferredTuple>]> = Narrow extends unknown[] ? {
    [key in keyof X]: _$infer<X[key]>;
} : Narrow;
/**
 * `Infer` is a type-level function that infers the most specific type of a value.
 *
 * @template X - The value to infer the type of.
 *
 * @example
 * type T0 = $<Infer, 'foo'> // 'foo'
 *
 * @example
 * // Demonstrating usage of Infer for const parameters in functions
 * function inferType<T>(x: $<Type.Infer, T>): typeof x {
 *   return x
 * }
 *
 * const x = inferType(['foo', { x: ['x'] }, 'bar', ['foo']])
 * // x is inferred as ['foo', { x: ['x'] }, 'bar', ['foo']]
 */
export interface Infer extends Kind.Kind {
    f(x: this[Kind._]): _$infer<typeof x>;
}
export {};