Add redirect time to TTFB breakdown about web-vitals HOT 5 CLOSED

/*
 * Copyright 2022 Google LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import {onTTFB as unattributedOnTTFB} from '../onTTFB.js';
import {
  TTFBMetric,
  TTFBMetricWithAttribution,
  TTFBReportCallback,
  TTFBReportCallbackWithAttribution,
  ReportOpts,
} from '../types.js';

const attributeTTFB = (metric: TTFBMetric): void => {
  if (metric.entries.length) {
    const navigationEntry = metric.entries[0];
    const activationStart = navigationEntry.activationStart || 0;

    const workerStart = Math.max(navigationEntry.workerStart - activationStart, activationStart);
    const dnsStart = Math.max(navigationEntry.domainLookupStart - activationStart, workerStart);
    const tcpStart = Math.max(navigationEntry.connectStart - activationStart, dnsStart);
    const sslStart = Math.max(navigationEntry.secureConnectionStart - activationStart, tcpStart);
    const requestStart = Math.max(navigationEntry.requestStart - activationStart, sslStart);
    const responseStart = Math.max(navigationEntry.responseStart - activationStart, requestStart);
   
    (metric as TTFBMetricWithAttribution).attribution = {
      redirectTime: workerStart - activationStart,
      workerAndCacheTime: dnsStart - workerStart,
      dnsTime: tcpStart - dnsStart,
      tcpTime: sslStart - tcpStart,
      sslTime: requestStart - sslStart,
      requestTime: responseStart - requestStart,
      navigationEntry: navigationEntry,
    };
    return;
  }
  // Set an empty object if no other attribution has been set.
  (metric as TTFBMetricWithAttribution).attribution = {
    redirectTime: 0,
    workerAndCacheTime: 0,
    dnsTime: 0,
    tcpTime: 0,
    sslTime: 0,
    requestTime: 0
  };
};

/**
 * Calculates the [TTFB](https://web.dev/articles/ttfb) value for the
 * current page and calls the `callback` function once the page has loaded,
 * along with the relevant `navigation` performance entry used to determine the
 * value. The reported value is a `DOMHighResTimeStamp`.
 *
 * Note, this function waits until after the page is loaded to call `callback`
 * in order to ensure all properties of the `navigation` entry are populated.
 * This is useful if you want to report on other metrics exposed by the
 * [Navigation Timing API](https://w3c.github.io/navigation-timing/). For
 * example, the TTFB metric starts from the page's [time
 * origin](https://www.w3.org/TR/hr-time-2/#sec-time-origin), which means it
 * includes time spent on DNS lookup, connection negotiation, network latency,
 * and server processing time.
 */
export const onTTFB = (
  onReport: TTFBReportCallbackWithAttribution,
  opts?: ReportOpts
) => {
  unattributedOnTTFB(
    ((metric: TTFBMetricWithAttribution) => {
      attributeTTFB(metric);
      onReport(metric);
    }) as TTFBReportCallback,
    opts
  );
};

/*
 * Copyright 2022 Google LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import type {Metric} from './base.js';
import {NavigationTimingPolyfillEntry} from './polyfills.js';

/**
 * A TTFB-specific version of the Metric object.
 */
export interface TTFBMetric extends Metric {
  name: 'TTFB';
  entries: PerformanceNavigationTiming[] | NavigationTimingPolyfillEntry[];
}

/**
 * An object containing potentially-helpful debugging information that
 * can be sent along with the TTFB value for the current page visit in order
 * to help identify issues happening to real-users in the field.
 */
export interface TTFBAttribution {
  
  /**
   * The total redirect time.s.
   */
  redirectTime: number;
  
  /**
   * The total worker and cache time.
   */
  workerAndCacheTime: number;
 
  /**
   * The total dns time.
   */
  dnsTime: number;
  
  /**
   * The total tcp time.
   */
  tcpTime: number;
 
  /**
   * The total ssl time.
   */
  sslTime: number;

  /**
   * The total reqquest  time.
   */
  requestTime: number;
  /**
   * The `navigation` entry of the current page, which is useful for diagnosing
   * general page load issues. This can be used to access `serverTiming` for example:
   * navigationEntry?.serverTiming
   */
  navigationEntry?: PerformanceNavigationTiming | NavigationTimingPolyfillEntry;
}

/**
 * A TTFB-specific version of the Metric object with attribution.
 */
export interface TTFBMetricWithAttribution extends TTFBMetric {
  attribution: TTFBAttribution;
}

/**
 * A TTFB-specific version of the ReportCallback function.
 */
export interface TTFBReportCallback {
  (metric: TTFBMetric): void;
}

/**
 * A TTFB-specific version of the ReportCallback function with attribution.
 */
export interface TTFBReportCallbackWithAttribution {
  (metric: TTFBMetricWithAttribution): void;
}