/**
 * Materialises freshly streamed text: every batch of characters appended to
 * the growing tail block enters through a blur that resolves as it settles.
 *
 * The hard part is that the tail block is re-rendered wholesale (`v-html`)
 * on every delta, which destroys any wrapper spans mid-animation. The fix is
 * to make the animation *stateless in the DOM*: chunks are registered by
 * character offset with their arrival time, and after every patch the still-
 * animating chunks are re-wrapped with a negative `animation-delay`, so each
 * one resumes exactly where the patch interrupted it. (A per-delta re-fade of
 * the whole tail element was tried long ago and retired — this is the version
 * that animates only what actually arrived.)
 */
export interface FreshChunksOptions {
    /** How long a chunk animates; older chunks stop being re-wrapped. */
    durationMs?: number;
    /** Class applied to the wrapper spans. */
    className?: string;
    /** Injectable clock, for tests. */
    now?: () => number;
}
export interface FreshChunks {
    /**
     * Re-syncs against the element's current text and wraps still-animating
     * chunks. Call after every DOM patch of the tracked tail block, post-flush
     * (the wrap must land in the same frame as the patch, before paint).
     */
    update: (el: HTMLElement, blockId: number | string) => void;
    /**
     * Adopts the element's current text as already shown: nothing in it
     * animates, and only what is appended after this call counts as fresh. For
     * content that was on screen before the tracker existed.
     */
    seed: (el: HTMLElement, blockId: number | string) => void;
    /** Unwraps every fresh span under `root` and forgets all chunks. */
    finish: (root: ParentNode) => void;
    reset: () => void;
}
export declare function createFreshChunks(options?: FreshChunksOptions): FreshChunks;