/**
 * EnvironmentVariables class is a wrapper around NodeJS.ProcessEnv to provide type-safe access to environment variables.
 */
export declare class EnvironmentVariables {
    private readonly env;
    /**
     * Creates a new instance of EnvironmentVariables.
     * @param env The NodeJS.ProcessEnv object.
     * @returns A new instance of EnvironmentVariables.
     */
    constructor(env?: NodeJS.ProcessEnv);
    /**
     * Gets the value of the environment variable.
     * @param key The key of the environment variable.
     * @returns The value of the environment variable or undefined.
     */
    getString(key: string): string | undefined;
    /**
     * Gets the value of the environment variable or the default value if the environment variable is not set.
     * @param key The key of the environment variable.
     * @param defaultValue The default value to return if the environment variable is not set.
     * @returns The value of the environment variable or the default value.
     */
    getStringOrDefault(key: string, defaultValue: string): string;
    /**
     * Gets the value of the environment variable as a number.
     * @param key The key of the environment variable.
     * @param defaultValue The default value to return if the environment variable is not set.
     * @returns The value of the environment variable as a number or the default value.
     */
    getNumber(key: string, defaultValue: number): number;
    /**
     * Gets the value of the environment variable as a boolean.
     * @param key The key of the environment variable.
     * @param defaultValue The default value to return if the environment variable is not set.
     * @returns The value of the environment variable as a boolean or the default value.
     */
    getBoolean(key: string, defaultValue: boolean): boolean;
    /**
     * Gets the value of the environment variable as an array.
     * @param key The key of the environment variable.
     * @param defaultValue The default value to return if the environment variable is not set.
     * @returns The value of the environment variable as an array or the default value.
     */
    getArray<T>(key: string, defaultValue: Array<T>): Array<T>;
    /**
     * Gets the value of the environment variable as an object.
     * @param key The key of the environment variable.
     * @param defaultValue The default value to return if the environment variable is not set.
     * @returns The value of the environment variable as an object or the default value.
     */
    getObject<T>(key: string, defaultValue: T): T;
}