/**
 * Progressive "typing" prefixes of rich-text HTML.
 *
 * A prefix keeps the markup well-formed: text nodes are cut mid-run, atomic
 * nodes (inline math, images, line breaks) are either fully in or fully out,
 * and elements left with nothing visible after the cut are dropped so no
 * empty paragraphs flash before their text arrives.
 */
/** Total typing units in `html` (characters plus a fixed weight per atomic node). */
export declare function revealUnits(html: string): number;
/** The first `units` typing units of `html` as well-formed HTML. */
export declare function revealPrefix(html: string, units: number): string;