predictype/dist/cjs/predicates/maps/mapKey.d.ts

PredicType is a library of pre-built and tested predicates for TypeScript, covering various data types and operations.

import { MapKeyOper } from '../../enums/maps.js';
/**
 * Checks if a Map contains (or lacks) a specific key using the specified operation.
 *
 * @param source The Map to check.
 * @param oper The key operation to perform (e.g. 'has_key', 'lacks_key').
 * @param key The key to check for.
 * @returns True if the key check is valid according to the operator, otherwise false.
 *
 * @throws {Error} If the operation is not recognized.
 *
 * @example
 * const m = new Map([[1, 'a']]);
 * const key1 = 1;
 * const key2 = 2;
 *
 * mapKey(m, 'has_key', key1); // true
 * mapKey(m, 'lacks_key', key2); // true
 *
 * @remarks
 * Supported Operators:
 * - **CONTAINS_KEY**: Map contains the key
 * - **LACKS_KEY**: Map does not contain the key
 */
export declare function mapKey<K, V>(source: Map<K, V>, oper: MapKeyOper, key: K): boolean;