export declare const featureSettingsProps: Set<string>;
export declare const fontVariantToOTTags: Record<string, Record<string, string[]>>;
export declare const UNRESOLVED_FEATURES_SENTINEL = "<unresolved>";
export declare function extractFeatureTagsFromDecl(prop: string, value: string): Set<string>;
interface PostCssRuleNode {
    type: string;
    prop: string;
    value: string;
}
interface PostCssRule {
    nodes: PostCssRuleNode[];
}
export declare function ruleFeatureTags(rule: PostCssRule): Set<string> | null;
export declare function ruleFontFamily(rule: PostCssRule): string | null;
export declare function addTagsToMapEntry<K>(map: Map<K, Set<string>>, key: K, tags: Iterable<string>): void;
export declare function recordRuleFeatureTags(rule: PostCssRule, featureTagsByFamily: Map<string, Set<string>> | null | undefined): true | string[] | null;
interface StylesheetEntry {
    asset?: {
        parseTree?: {
            walkRules?(cb: (rule: PostCssRule) => void): void;
        };
    };
}
export declare function findFontFamiliesWithFeatureSettings(stylesheetsWithPredicates: StylesheetEntry[], featureTagsByFamily: Map<string, Set<string>> | null | undefined): true | Set<string> | null;
export declare function resolveFeatureSettings(fontFamilies: Iterable<string>, fontFamiliesWithFeatureSettings: true | Set<string> | null | undefined, featureTagsByFamily: Map<string, Set<string>> | null | undefined): {
    hasFontFeatureSettings: boolean;
    fontFeatureTags?: string[];
};
export {};
//# sourceMappingURL=fontFeatureHelpers.d.ts.map