fix: cache dynamic imports (#8652)

src/common/DOMWorld.ts

@@ -29,6 +29,7 @@ import {TimeoutSettings} from './TimeoutSettings.js';
 import {EvaluateFunc, HandleFor, NodeFor} from './types.js';
 import {
   debugError,
+  importFS,
   isNumber,
   isString,
   makePredicateString,
@@ -429,7 +430,7 @@ export class DOMWorld {
     if (path !== null) {
       let fs: typeof import('fs').promises;
       try {
-        fs = (await import('fs')).promises;
+        fs = (await importFS()).promises;
       } catch (error) {
         if (error instanceof TypeError) {
           throw new Error(

src/common/Debug.ts

@@ -21,6 +21,20 @@ declare global {
   var __PUPPETEER_DEBUG: string;
 }
 
+/**
+ * @internal
+ */
+let debugModule: typeof import('debug') | null = null;
+/**
+ * @internal
+ */
+export async function importDebug(): Promise<typeof import('debug')> {
+  if (!debugModule) {
+    debugModule = (await import('debug')).default;
+  }
+  return debugModule;
+}
+
 /**
  * A debug function that can be used in any environment.
  *
@@ -61,7 +75,7 @@ declare global {
 export const debug = (prefix: string): ((...args: unknown[]) => void) => {
   if (isNode) {
     return async (...logArgs: unknown[]) => {
-      (await import('debug')).default(prefix)(logArgs);
+      (await importDebug())(prefix)(logArgs);
     };
   }
 

src/common/Page.ts

@@ -55,6 +55,7 @@ import {
   debugError,
   evaluationString,
   getExceptionMessage,
+  importFS,
   getReadableAsBuffer,
   getReadableFromProtocolStream,
   isErrorLike,
@@ -2920,7 +2921,7 @@ export class Page extends EventEmitter {
 
     if (options.path) {
       try {
-        const fs = (await import('fs')).promises;
+        const fs = (await importFS()).promises;
         await fs.writeFile(options.path, buffer);
       } catch (error) {
         if (error instanceof TypeError) {

src/common/util.ts

@@ -412,6 +412,20 @@ export async function waitWithTimeout<T>(
   }
 }
 
+/**
+ * @internal
+ */
+let fs: typeof import('fs') | null = null;
+/**
+ * @internal
+ */
+export async function importFS(): Promise<typeof import('fs')> {
+  if (!fs) {
+    fs = await import('fs');
+  }
+  return fs;
+}
+
 /**
  * @internal
  */
@@ -423,7 +437,7 @@ export async function getReadableAsBuffer(
   if (path) {
     let fs: typeof import('fs').promises;
     try {
-      fs = (await import('fs')).promises;
+      fs = (await importFS()).promises;
     } catch (error) {
       if (error instanceof TypeError) {
         throw new Error(