@monstermann/fn/dist/object/hasKey.d.ts

A utility library for TypeScript.

import { KeysOfUnion, Simplify } from "type-fest";

//#region src/object/hasKey.d.ts
type HasKey<T extends object, U extends KeysOfUnion<T>> = T extends unknown ? U extends keyof T ? Simplify<T & Record<U, Required<T>[U]>> : never : never;
/**
 * `hasKey(target, key)`
 *
 * Checks if `target` object has the specified `key` property.
 *
 * ```ts
 * hasKey({ a: 1, b: 2 }, "a"); // true
 * hasKey({ a: 1, b: 2 }, "c"); // false
 * ```
 *
 * ```ts
 * pipe({ a: 1, b: 2 }, hasKey("a")); // true
 * pipe({ a: 1, b: 2 }, hasKey("c")); // false
 * ```
 */
declare const hasKey: {
  <T extends object, U extends KeysOfUnion<T>>(key: U): (target: T) => target is HasKey<T, U>;
  <T extends object, U extends KeysOfUnion<T>>(target: T, key: U): target is HasKey<T, U>;
};
//#endregion
export { hasKey };