/**
 * JS/CSS coverage collector via Playwright's built-in coverage API.
 *
 * For each crawled page, records what percentage of loaded JS/CSS was actually
 * executed/applied. High unused code % → performance opportunity (code splitting, lazy loading).
 *
 * Uses Playwright's page.coverage API (wraps CDP Coverage domain).
 */
import type { Page } from 'playwright';
export interface CoverageEntry {
    url: string;
    type: 'js' | 'css';
    totalBytes: number;
    usedBytes: number;
    unusedPercent: number;
}
export interface CoverageReport {
    pageUrl: string;
    entries: CoverageEntry[];
    totalJsBytes: number;
    usedJsBytes: number;
    totalCssBytes: number;
    usedCssBytes: number;
    jsUnusedPercent: number;
    cssUnusedPercent: number;
    collectedAt: string;
}
export declare function startCoverage(page: Page): Promise<void>;
export declare function stopAndCollectCoverage(page: Page, pageUrl: string): Promise<CoverageReport | null>;