import { NumberRuleChecker } from './number-rule-checker';
import { GuardResult } from '../../core/guard-result';
export declare class NumberIsFibonacci extends NumberRuleChecker<{
    type: 'isFibonacci';
    allowNegative?: boolean;
}> {
    constructor(rule: {
        type: 'isFibonacci';
        allowNegative?: boolean;
    }, value: number);
    /**
     * @override
     */
    exec(): GuardResult;
    /**
     * Checks if number is a Fibonacci number.
     * @remarks n is a Fibonacci number if n is equal or greater than zero, and of the following conditions is fulfilled:
     * - 5n²+4 is a perfect square.
     * - 5n²-4 is a perfect square.
     */
    private isFibonacci;
    /**
     * Checks if number is a NegaFibonacci number.
     * @remarks n is a NegaFibonacci number if one of the following conditions is fulfilled:
     * - 5n²+4 is a perfect square.
     * - 5n²-4 is a perfect square.
     */
    private isNegaFibonacci;
    /**
     * Checks if number is a perfect square.
     * @remarks Perfect squares are the squares of the whole numbers: 1, 4, 9, 16, 25, 36, 49...
     * @param value
     */
    private isPerfectSquare;
}