predictype/dist/cjs/predicates/promises/promiseType.js

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

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.promiseType = promiseType;
const promises_js_1 = require("../../enums/promises.js");
/**
 * Checks if a value is a Promise or an async function using the specified operation.
 *
 * @param source The value to check.
 * @param oper The type operation to perform (e.g. 'is_promise', 'is_async_function').
 * @returns True if the type check is valid according to the operator, otherwise false.
 *
 * @throws {Error} If the operation is not recognized.
 *
 * @example
 * const p = Promise.resolve(42);
 * async function foo() {}
 *
 * promiseType(p, 'is_promise'); // true
 * promiseType(foo, 'is_async_function'); // true
 *
 * @remarks
 * Supported Operators:
 * - **IS_PROMISE**: Value is a Promise
 * - **IS_ASYNC_FUNCTION**: Value is an async function
 */
function promiseType(source, oper) {
    const operators = {
        [promises_js_1.PromiseTypeEnum.IS_PROMISE]: (a) => typeof a === 'object' && a !== null && typeof a.then === 'function',
        [promises_js_1.PromiseTypeEnum.IS_ASYNC_FUNCTION]: (a) => typeof a === 'function' && a.constructor.name === 'AsyncFunction',
    };
    const enumOper = typeof oper === 'string' ? oper : oper;
    const fn = operators[enumOper];
    if (!fn)
        throw new Error(`Unknown PromiseType operation: ${oper}`);
    return fn(source);
}