import { EnvironmentFactory } from "./types";
import { ObjectAccumulator } from "typed-object-accumulator";
/**
 * @class Environment
 * @extends {ObjectAccumulator<T>}
 * @template T
 * @description A class representing an environment with accumulation capabilities.
 * @summary Manages environment-related data and provides methods for accumulation and key retrieval.
 * @param {T} [initialData] - The initial data to populate the environment with.
 */
export declare class Environment<T extends object> extends ObjectAccumulator<T> {
    /**
     * @static
     * @protected
     * @description A factory function for creating Environment instances.
     * @summary Defines how new instances of the Environment class should be created.
     * @return {Environment<any>} A new instance of the Environment class.
     */
    protected static factory: EnvironmentFactory<any, any>;
    /**
     * @static
     * @private
     * @description The singleton instance of the Environment class.
     * @type {Environment<any>}
     */
    private static _instance;
    protected constructor();
    protected fromEnv(k: string): unknown;
    protected expand<V extends object>(value: V): void;
    /**
     * @protected
     * @static
     * @description Retrieves or creates the singleton instance of the Environment class.
     * @summary Ensures only one instance of the Environment class exists.
     * @template E
     * @param {...unknown[]} args - Arguments to pass to the factory function if a new instance is created.
     * @return {E} The singleton instance of the Environment class.
     */
    protected static instance<E extends Environment<any>>(...args: unknown[]): E;
    /**
     * @static
     * @description Accumulates the given value into the environment.
     * @summary Adds new properties to the environment from the provided object.
     * @template V
     * @param {V} value - The object to accumulate into the environment.
     * @return {V} The updated environment instance.
     */
    static accumulate<V extends object>(value: V): typeof Environment._instance & V & ObjectAccumulator<typeof Environment._instance & V>;
    /**
     * @static
     * @description Retrieves the keys of the environment, optionally converting them to ENV format.
     * @summary Gets all keys in the environment, with an option to format them for environment variables.
     * @param {boolean} [toEnv=true] - Whether to convert the keys to ENV format.
     * @return {string[]} An array of keys from the environment.
     */
    static keys(toEnv?: boolean): string[];
}