export declare class NiceConfig {
    private options?;
    private bootstrapConfig;
    private Config;
    private getOptions;
    /**
     * Reads an application's configuration properties from various sources
     * and merges them into a single configuration object.
     *
     * @param {NiceConfigOptions} options The config options that drive behavior here.
     * @returns {ConfigObject} The merged configuration properties from all sources.
     */
    private readConfig;
    /**
     * Initialize the config instance by reading all property sources.
     *
     * @param {NiceConfigOptions} options The config options that drive behavior here.
     * @returns {ConfigObject} The merged configuration properties from all sources.
     */
    load: () => Promise<Record<string, any>>;
    instance: () => Record<string, any>;
}