import type { LoadOptions } from "../types.js";
/**
 * EnvLoader helpers
 *
 * @example
 * ```ts
 * EnvLoader.loadWithPrecedence([
 *   "/etc/internal-secrets.env",
 *   "/etc/default/myapp",
 *   path.join(process.cwd(), ".env"),
 * ]);
 * ```
 */
export declare const EnvLoader: {
    /**
     * Load with precedence: later files override earlier ones
     *
     * @param paths
     * @param options
     * @returns
     */
    loadWithPrecedence: (paths: string[], options?: Omit<LoadOptions, "paths">) => boolean;
    /**
     * Load system and app envs
     *
     * @param appEnvPath
     * @returns
     */
    loadSystemAndApp: (appEnvPath?: string) => boolean;
    /**
     * Load for different environments
     * @param env
     * @returns
     */
    loadForEnvironment: (env: "development" | "staging" | "production" | (string & {})) => boolean;
};
export declare function getEnv(key: keyof NodeJS.ProcessEnv | (string & {}), defaultValue?: string): string;
/**
 * Check if variables are loaded
 *
 * @param keys
 * @returns
 */
export declare function hasKeys(...keys: (keyof NodeJS.ProcessEnv | (string & {}))[]): boolean;
/**
 * Get all loaded keys from specific files
 *
 * @param filePaths
 * @returns
 */
export declare function getKeys(filePaths?: string[]): Map<string, string[]>;