import { ISetNextTick } from "./interfaces";

export let setNextTick: ISetNextTick;

if (setImmediate === undefined) {

    setNextTick = function(fn: Function, ...args: any[]): void {

        setTimeout(fn, 0, ...args);
    };
}
else {

    setNextTick = setImmediate;
}

/**
 * Wrap and limit a function to be called only once.
 */
export function once<T>(callback: T): T {

    let called: boolean = false;

    let ret: any = function(...args: any[]): void {

        if (called) {

            throw new Error("Duplicated invocation to a invoked callback.");
        }

        called = true;

        (<Function><any>callback)(...args);
    };

    return ret;
}