predictype/dist/cjs/predicates/promises/promiseState.d.ts

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

import { PromiseStateOper } from '../../enums/promises.js';
export type PromiseWithState<T> = {
    promise: Promise<T>;
    state: PromiseStateOper;
};
export declare function wrapPromise<T>(p: Promise<T>): PromiseWithState<T>;
/**
 * Checks the state of a wrapped Promise using the specified operation.
 *
 * Note: This predicate requires a wrapper or custom Promise implementation that exposes state.
 * Standard JS Promises do not expose their state synchronously.
 *
 * @param wrapper The wrapped Promise with state.
 * @param oper The state operation to perform (e.g. 'is_pending', 'is_fulfilled').
 * @returns True if the state check is valid according to the operator, otherwise false.
 *
 * @throws {Error} If the operation is not recognized.
 *
 * @example
 * const p = Promise.resolve(42);
 * const wrapped = wrapPromise(p);
 *
 * promiseState(wrapped, 'is_pending'); // true (immediately after wrapping)
 *
 * @remarks
 * Supported Operators:
 * - **IS_PENDING**: Promise is pending
 * - **IS_FULFILLED**: Promise is fulfilled
 * - **IS_REJECTED**: Promise is rejected
 */
export declare function promiseState<T>(wrapper: PromiseWithState<T>, oper: PromiseStateOper): boolean;