import * as EngineConst from './engine_const.js';
export declare class Options {
    static BINARY_FEATURES: string[];
    static STRING_FEATURES: string[];
    delay: boolean;
    domain: string;
    style: string;
    locale: string;
    subiso: string;
    modality: string;
    speech: EngineConst.Speech;
    markup: EngineConst.Markup;
    mark: boolean;
    automark: boolean;
    character: boolean;
    cleanpause: boolean;
    cayleyshort: boolean;
    linebreaks: boolean;
    rate: string;
    walker: string;
    structure: boolean;
    aria: boolean;
    tree: boolean;
    strict: boolean;
    pprint: boolean;
    rules: string;
    prune: string;
    constructor(options?: {
        [key: string]: boolean | string;
    });
    set(options: {
        [key: string]: boolean | string;
    }): void;
    json(): {
        [key: string]: boolean | string;
    };
    private ensureDomain;
}