/**
 * Keep track of vocabulary prefixes.
 */
export declare const KNOWN_VOCABULARIES: {
    [prefix: string]: string;
};
export interface HtmlValueMap {
    [tagName: string]: (attrs: {
        [key: string]: string;
    }, baseUrl: string) => string | undefined;
}
/**
 * Grab the correct attribute for RDFa support.
 */
export declare const HTML_VALUE_MAP: HtmlValueMap;
export interface HandlerContext {
    tagName: string;
    text: string;
    flags: number;
    attributes: {
        [key: string]: string;
    };
    rdfaTextProperty?: string[];
    microdataTextProperty?: string[];
}
export declare const HandlerFlags: {
    hasLang: number;
    rdfaLink: number;
    rdfaNode: number;
    rdfaVocab: number;
    microdataNode: number;
    microdataVocab: number;
    microdataScope: number;
};
export interface ResultTwitter {
    card?: string;
    site?: string;
    "site:id"?: string;
    creator?: string;
    "creator:id"?: string;
    description?: string;
    title?: string;
    image?: string;
    "image:alt"?: string;
    player?: string;
    "player:width"?: string;
    "player:height"?: string;
    "player:stream"?: string;
    "app:name:iphone"?: string;
    "app:id:iphone"?: string;
    "app:url:iphone"?: string;
    "app:name:ipad"?: string;
    "app:id:ipad"?: string;
    "app:url:ipad"?: string;
    "app:name:googleplay"?: string;
    "app:id:googleplay"?: string;
    "app:url:googleplay"?: string;
    [key: string]: string | undefined;
}
export interface ResultDublinCore {
    title?: string;
    date?: string;
    "date.issued"?: string;
    "date.modified"?: string;
    [key: string]: string | undefined;
}
export interface ResultSailthru {
    title?: string;
    description?: string;
    author?: string;
    tags?: string;
    date?: string;
    expire_date?: string;
    "image.full"?: string;
    "image.thumb"?: string;
    location?: string;
    price?: string;
    [key: string]: string | undefined;
}
export interface ResultApplinks {
    "ios:url"?: string;
    "ios:app_store_id"?: string;
    "ios:app_name"?: string;
    "iphone:url"?: string;
    "iphone:app_store_id"?: string;
    "iphone:app_name"?: string;
    "ipad:url"?: string;
    "ipad:app_store_id"?: string;
    "ipad:app_name"?: string;
    "android:url"?: string;
    "android:package"?: string;
    "android:class"?: string;
    "android:app_name"?: string;
    "windows_phone:url"?: string;
    "windows_phone:app_id"?: string;
    "windows_phone:app_name"?: string;
    "windows:url"?: string;
    "windows:app_id"?: string;
    "windows:app_name"?: string;
    "windows_universal:url"?: string;
    "windows_universal:app_id"?: string;
    "windows_universal:app_name"?: string;
    "web:url"?: string;
    "web:should_fallback"?: string;
    [key: string]: string | undefined;
}
export interface ResultHtml {
    date?: string;
    keywords?: string;
    author?: string;
    description?: string;
    language?: string;
    generator?: string;
    creator?: string;
    publisher?: string;
    robots?: string;
    viewport?: string;
    "application-name"?: string;
    "apple-mobile-web-app-title"?: string;
    title?: string;
    canonical?: string;
    amphtml?: string;
    pingback?: string;
    [key: string]: string | undefined;
}
export interface Alternative {
    type: string;
    href: string;
    title?: string;
    media?: string;
    hreflang?: string;
}
export interface Icon {
    type?: string;
    sizes?: string;
    href: string;
}
export interface Link {
    href: string;
    text: string;
    download: boolean;
    hreflang?: string;
    rel?: string;
    type?: string;
    target?: string;
}
export interface Image {
    src: string;
    alt?: string;
    longdesc?: string;
    sizes?: string[];
    srcset?: string[];
}
export interface Result {
    alternate: Array<Alternative>;
    icons: Array<Icon>;
    links: Array<Link>;
    images: Array<Image>;
    jsonld?: RdfaNode[];
    rdfa?: RdfaNode[];
    microdata?: RdfaNode[];
    applinks?: ResultApplinks;
    twitter?: ResultTwitter;
    dublincore?: ResultDublinCore;
    sailthru?: ResultSailthru;
    html?: ResultHtml;
}
export interface Options {
    url: string;
}
export interface RdfaNode {
    "@id"?: string;
    "@context"?: {
        [key: string]: string;
    };
    [key: string]: unknown;
}
export declare class Handler {
    protected callback: (err: Error | null, result: Result) => void;
    protected options: Options;
    protected result: Result;
    protected contexts: HandlerContext[];
    protected langs: string[];
    private _rdfaNodes;
    private _rdfaVocabs;
    private _rdfaRels;
    private _microdataRefs;
    private _microdataScopes;
    private _microdataNodes;
    constructor(callback: (err: Error | null, result: Result) => void, options: Options);
    onend(): void;
    onerror(error: Error): void;
    onopentag(tagName: string, attributes: {
        [attribute: string]: string;
    }): void;
    ontext(value: string): void;
    onclosetag(): void;
    /**
     * Add a microdata property, with support for `id` references (used via `itemref`).
     */
    private _addMicrodataProperty;
    /**
     * Set a microdata property.
     */
    private _setMicrodataProperty;
    /**
     * Add an RDFa property to the node.
     */
    private _addRdfaProperty;
    /**
     * Correct known prefixes in the context.
     */
    private _normalizeRdfaProperty;
    /**
     * Create an RDFa resource.
     */
    private _createRdfaResource;
}
/**
 * Copy properties from `a` to `b`, when "defined".
 */
export declare function copy<T extends {
    [key: string]: unknown;
}>(a: T, b: T): void;