import type { Feature } from '../process.spec.js';
import type { GlyphObject } from '../glyph/glyph.spec.js';
/**
 * Sort features or glyph features
 * @param a - first feature
 * @param b - comparison feature
 * @returns a negative value if a < b, 0 if a === b, and a positive value if a > b
 */
export declare function featureSort(a: Feature | GlyphObject, b: Feature | GlyphObject): number;