Page Metrics

import puppeteer from "@cloudflare/puppeteer";import type { Page } from "@cloudflare/puppeteer";import { DEFAULT_VIEWPORT, NAVIGATION_TIMEOUT_MS } from "../constants/defaults";import type { PageMetricsResponse } from "../types/metrics";export async function withBrowserPage<T>(  browserBinding: Fetcher,  url: string,  fn: (page: Page) => Promise<T>): Promise<T> {  let browser: Awaited<ReturnType<typeof puppeteer.launch>> | null = null;  try {    browser = await puppeteer.launch(browserBinding);    const page = await browser.newPage();    await page.setViewport(DEFAULT_VIEWPORT);    await page.goto(url, {      waitUntil: "networkidle0",      timeout: NAVIGATION_TIMEOUT_MS,    });    return await fn(page);  } finally {    if (browser) {      try {        await browser.close();      } catch {        /* ignore close errors */      }    }  }}export function normalizeMetrics(raw: Record<string, number>): Record<string, number> {  const normalized: Record<string, number> = {};  for (const [key, value] of Object.entries(raw)) {    if (typeof value === "number" && Number.isFinite(value)) {      normalized[key] = Math.round(value * 1000) / 1000;    }  }  return normalized;}export async function collectPageMetrics(  browserBinding: Fetcher,  url: string): Promise<PageMetricsResponse> {  const metrics = await withBrowserPage(browserBinding, url, async (page) => page.metrics());  return {    url,    metrics: normalizeMetrics(metrics as Record<string, number>),  };}