/**
 * @public
 */
export declare enum LanguageTagField {
    LANGUAGE = 0,
    SCRIPT = 1,
    REGION = 2,
    VARIANT = 3
}
/**
 * IETF BCP 47 language tag with static methods for parsing, adding likely
 * subtags, etc.
 *
 * @public
 */
export declare class LanguageTag {
    protected core: (undefined | string)[];
    protected _extensions: {
        [x: string]: string[];
    };
    protected _privateUse: string;
    protected _extlangs: string[];
    protected _compact?: string;
    protected _expanded?: string;
    constructor(language?: string, script?: string, region?: string, variant?: string, extensions?: {
        [x: string]: string[];
    }, privateUse?: string, extlangs?: string[]);
    /**
     * Language subtag.
     */
    language(): string;
    /**
     * Returns true if the language subtag is defined.
     */
    hasLanguage(): boolean;
    /**
     * Script subtag.
     */
    script(): string;
    /**
     * Returns true if the script subtag is defined.
     */
    hasScript(): boolean;
    /**
     * Region subtag.
     */
    region(): string;
    /**
     * Returns true if the region subtag is defined.
     */
    hasRegion(): boolean;
    /**
     * Variant subtag.
     */
    variant(): string;
    /**
     * Return a copy of this language tag's extensions map.
     */
    extensions(): {
        [x: string]: string[];
    };
    /**
     * Return a copy of the extensions of the given type. Use 'u' for Unicode
     * and 't' for Transforms.
     */
    extensionSubtags(key: string): string[];
    /**
     * Private use subtag.
     */
    privateUse(): string;
    /**
     * Extended language tags, used for BCP 47 canonicalization.
     */
    extlangs(): string[];
    /**
     * Return a compact string representation of the language tag. Any undefined
     * fields will be omitted.
     */
    compact(): string;
    /**
     * Return an expanded string representation of the language tag. Any undefined
     * fields will emit their undefined value.
     */
    expanded(): string;
    /**
     * Return a compact string representation of the language tag. Any undefined
     * fields will be omitted.
     */
    toString(): string;
    /**
     * Render a tag in compact or expanded form.
     */
    private render;
}