export declare function format(first: string, middle: string, last: string): string;
export declare const REVEAL_BASE_CPS = 140;
export declare const REVEAL_MAX_LAG_S = 1.2;
export declare const REVEAL_DRAIN_S = 0.4;
/** Characters to reveal this frame. ``carry`` accumulates fractional
 * characters across frames so low rates still advance; returns the chars to
 * reveal plus the new carry. */
export declare function revealStep(backlogChars: number, dtSeconds: number, carry: number, maxLagSeconds?: number): {
    chars: number;
    carry: number;
};
/** Avoid ending a reveal slice between the halves of a surrogate pair, which
 * would transiently render a replacement character. */
export declare function extendPastSurrogate(text: string, end: number): number;
/** When a slice ends at the very end of the backlog on a high surrogate, the
 * low half hasn't streamed in yet and extending is impossible; retreat one
 * character so the pair is revealed together once its second half arrives. */
export declare function retreatBeforeTrailingSurrogate(text: string, end: number): number;