/**
 * create a singleton using the function provided.
 * @param func - a function that will be called to create the instance.
 * @returns A function that return a singleton instance of the type T for a given label.
 */
declare function createSingleton<T>(func: (...args: any[]) => T): (label?: string, ...args: any[]) => T;
/**
 * given a function fn, repeat it every interval milliseconds.
 * rc.start() to start the repeater
 * rc.stop() to stop the repeater
 * createRepeater(fn, 5000); // run fn every 5 seconds
 * @param fn
 * @param interval
 * @returns
 */
declare function createRepeater(fn: Function, interval: number): {
    start(): void;
    stop(): void;
};
type StepFn<I, A extends any[], O> = (value: I, ...args: A) => O | Promise<O>;
declare class Chainer<T> extends Promise<T> {
    private chainPromise;
    constructor(initial: T);
    step<A extends any[], R>(fn: StepFn<T, A, R>, ...args: any[]): Chainer<R>;
    s<A extends any[], R>(fn: StepFn<T, A, R>, ...args: any[]): Chainer<R>;
    static from<T>(initial: T): Chainer<T>;
}
/**
 * chains multiple functions/steps together. Each step can be synchronous or asynchronous.
 * Each step receives the result of the previous step as the first parameter. more parameters can be passed after that.
 * To calculate the final result, use `await` on the returned Chainer.
 * @param initial initial value to start
 * @returns final result
 * @example
 * ```ts
 * import { chainer } from "@devbro/pashmak/helpers";
 * const add = (x: number, y: number, z: number) => x + y + z;
 * const multiply = (x: number, y: number) => x * y;
 *
 * const result = await chainer(4)
 *   .step(add, 2, 0)        // 4 + 2 = 6
 *   .step(multiply, 3)   // 6 * 3 = 18
 */
declare function chainer<T>(initial: T): Chainer<T>;
/**
 * Checks if a variable is a class constructor.
 * @param variable - The variable to check
 * @returns True if the variable is a class, false otherwise
 */
declare function isClass(variable: any): boolean;
/**
 * Checks if a variable is a function (but not a class constructor).
 * @param variable - The variable to check
 * @returns True if the variable is a function and not a class, false otherwise
 */
declare function isFunction(variable: any): boolean;

export { chainer, createRepeater, createSingleton, isClass, isFunction };