fix: align network conditions presets with DevTools (#12542)

docs/api/index.md

@@ -1342,7 +1342,7 @@ Enum of valid mouse buttons.
 
 </td><td>
 
-A list of network conditions to be used with [Page.emulateNetworkConditions()](./puppeteer.page.emulatenetworkconditions.md).
+A list of pre-defined network conditions to be used with [Page.emulateNetworkConditions()](./puppeteer.page.emulatenetworkconditions.md).
 
 </td></tr>
 <tr><td>

docs/api/puppeteer.predefinednetworkconditions.md

@@ -4,7 +4,7 @@ sidebar_label: PredefinedNetworkConditions
 
 # PredefinedNetworkConditions variable
 
-A list of network conditions to be used with [Page.emulateNetworkConditions()](./puppeteer.page.emulatenetworkconditions.md).
+A list of pre-defined network conditions to be used with [Page.emulateNetworkConditions()](./puppeteer.page.emulatenetworkconditions.md).
 
 #### Signature:
 
@@ -12,6 +12,8 @@ A list of network conditions to be used with [Page.emulateNetworkConditions()](.
 PredefinedNetworkConditions: Readonly<{
   'Slow 3G': NetworkConditions;
   'Fast 3G': NetworkConditions;
+  'Slow 4G': NetworkConditions;
+  'Fast 4G': NetworkConditions;
 }>;
 ```
 
@@ -19,12 +21,16 @@ PredefinedNetworkConditions: Readonly<{
 
 ```ts
 import {PredefinedNetworkConditions} from 'puppeteer';
-const slow3G = PredefinedNetworkConditions['Slow 3G'];
-
 (async () => {
   const browser = await puppeteer.launch();
   const page = await browser.newPage();
-  await page.emulateNetworkConditions(slow3G);
+  await page.emulateNetworkConditions(PredefinedNetworkConditions['Slow 3G']);
+  await page.goto('https://www.google.com');
+  await page.emulateNetworkConditions(PredefinedNetworkConditions['Fast 3G']);
+  await page.goto('https://www.google.com');
+  await page.emulateNetworkConditions(PredefinedNetworkConditions['Slow 4G']); // alias to Fast 3G.
+  await page.goto('https://www.google.com');
+  await page.emulateNetworkConditions(PredefinedNetworkConditions['Fast 4G']);
   await page.goto('https://www.google.com');
   // other actions...
   await browser.close();

packages/puppeteer-core/src/cdp/PredefinedNetworkConditions.ts

@@ -7,19 +7,31 @@
 import type {NetworkConditions} from './NetworkManager.js';
 
 /**
- * A list of network conditions to be used with
+ * A list of pre-defined network conditions to be used with
  * {@link Page.emulateNetworkConditions}.
  *
  * @example
  *
  * ```ts
  * import {PredefinedNetworkConditions} from 'puppeteer';
- * const slow3G = PredefinedNetworkConditions['Slow 3G'];
- *
  * (async () => {
  *   const browser = await puppeteer.launch();
  *   const page = await browser.newPage();
- *   await page.emulateNetworkConditions(slow3G);
+ *   await page.emulateNetworkConditions(
+ *     PredefinedNetworkConditions['Slow 3G']
+ *   );
+ *   await page.goto('https://www.google.com');
+ *   await page.emulateNetworkConditions(
+ *     PredefinedNetworkConditions['Fast 3G']
+ *   );
+ *   await page.goto('https://www.google.com');
+ *   await page.emulateNetworkConditions(
+ *     PredefinedNetworkConditions['Slow 4G']
+ *   ); // alias to Fast 3G.
+ *   await page.goto('https://www.google.com');
+ *   await page.emulateNetworkConditions(
+ *     PredefinedNetworkConditions['Fast 4G']
+ *   );
  *   await page.goto('https://www.google.com');
  *   // other actions...
  *   await browser.close();
@@ -29,14 +41,40 @@ import type {NetworkConditions} from './NetworkManager.js';
  * @public
  */
 export const PredefinedNetworkConditions = Object.freeze({
+  // Generally aligned with DevTools
+  // https://source.chromium.org/chromium/chromium/src/+/main:third_party/devtools-frontend/src/front_end/core/sdk/NetworkManager.ts;l=398;drc=225e1240f522ca684473f541ae6dae6cd766dd33.
   'Slow 3G': {
+    // ~500Kbps down
     download: ((500 * 1000) / 8) * 0.8,
+    // ~500Kbps up
     upload: ((500 * 1000) / 8) * 0.8,
+    // 400ms RTT
     latency: 400 * 5,
   } as NetworkConditions,
   'Fast 3G': {
+    // ~1.6 Mbps down
     download: ((1.6 * 1000 * 1000) / 8) * 0.9,
+    // ~0.75 Mbps up
     upload: ((750 * 1000) / 8) * 0.9,
+    // 150ms RTT
     latency: 150 * 3.75,
   } as NetworkConditions,
+  // alias to Fast 3G to align with Lighthouse (crbug.com/342406608)
+  // and DevTools (crbug.com/342406608),
+  'Slow 4G': {
+    // ~1.6 Mbps down
+    download: ((1.6 * 1000 * 1000) / 8) * 0.9,
+    // ~0.75 Mbps up
+    upload: ((750 * 1000) / 8) * 0.9,
+    // 150ms RTT
+    latency: 150 * 3.75,
+  } as NetworkConditions,
+  'Fast 4G': {
+    // 9 Mbps down
+    download: ((9 * 1000 * 1000) / 8) * 0.9,
+    // 1.5 Mbps up
+    upload: ((1.5 * 1000 * 1000) / 8) * 0.9,
+    // 60ms RTT
+    latency: 60 * 2.75,
+  } as NetworkConditions,
 });