From e0025aec25fe7e4dfd3e45b6f90c01eef96d91ff Mon Sep 17 00:00:00 2001
From: Josh Grime <33323152+joshgrime@users.noreply.github.com>
Date: Thu, 27 Aug 2020 01:20:36 +0100
Subject: [PATCH 1/3] Added default fallback for exposeFunction using imported
 modules

---
 src/common/Page.ts | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/common/Page.ts b/src/common/Page.ts
index 211b1bcba8475..25d37f7dd1349 100644
--- a/src/common/Page.ts
+++ b/src/common/Page.ts
@@ -1052,6 +1052,14 @@ export class Page extends EventEmitter {
       throw new Error(
         `Failed to add page binding with name ${name}: window['${name}'] already exists!`
       );
+
+    if (
+      typeof puppeteerFunction !== 'function' &&
+      typeof puppeteerFunction['default'] === 'function'
+    ) {
+      puppeteerFunction = puppeteerFunction['default'];
+    }
+
     this._pageBindings.set(name, puppeteerFunction);
 
     const expression = helper.evaluationString(addPageBinding, name);

From c82bd64c85c1fce83f8663e5fb6ba3a7ee0f9786 Mon Sep 17 00:00:00 2001
From: Josh Grime <33323152+joshgrime@users.noreply.github.com>
Date: Mon, 14 Sep 2020 16:38:24 +0100
Subject: [PATCH 2/3] Added test for default fallback

---
 test/page.spec.ts | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/test/page.spec.ts b/test/page.spec.ts
index 9d7c5138868ec..4a4e5ab012404 100644
--- a/test/page.spec.ts
+++ b/test/page.spec.ts
@@ -900,6 +900,21 @@ describe('Page', function () {
       );
       expect(result.x).toBe(7);
     });
+    it('should fallback to default export when passed a module object', async () => {
+      const { page, server } = getTestState();
+      await page.goto(server.EMPTY_PAGE);
+      var moduleObject = {
+        default: function(a, b) {
+                  return a * b;
+                }
+              };
+      // @ts-expect-error
+      await page.exposeFunction('compute', moduleObject);
+      const result = await page.evaluate(async function () {
+        return await globalThis.compute(9, 4);
+      });
+      expect(result).toBe(36);
+    });
   });
 
   describeFailsFirefox('Page.Events.PageError', function () {
@@ -1274,6 +1289,9 @@ describe('Page', function () {
         .catch((error_) => (error = error_));
       expect(error).toBeTruthy();
     });
+
+
+
   });
 
   describe('Page.addStyleTag', function () {

From feeb48ed279b38cd925e57662234660ce6330c12 Mon Sep 17 00:00:00 2001
From: Jan Scheffler <janscheffler@chromium.org>
Date: Wed, 15 Sep 2021 21:22:53 +0200
Subject: [PATCH 3/3] chore: update documentation and types

---
 docs/api.md        |  2 +-
 src/common/Page.ts | 18 +++++++++++-------
 test/page.spec.ts  | 14 +++++---------
 3 files changed, 17 insertions(+), 17 deletions(-)

diff --git a/docs/api.md b/docs/api.md
index cd56decf2fbd0..434f3434a4859 100644
--- a/docs/api.md
+++ b/docs/api.md
@@ -1868,7 +1868,7 @@ await page.evaluateOnNewDocument(preloadFile);
 #### page.exposeFunction(name, puppeteerFunction)
 
 - `name` <[string]> Name of the function on the window object
-- `puppeteerFunction` <[function]> Callback function which will be called in Puppeteer's context.
+- `puppeteerFunction` <[function]> Callback function which will be called in Puppeteer's context. Can also be a module with a default export.
 - returns: <[Promise]>
 
 The method adds a function called `name` on the page's `window` object.
diff --git a/src/common/Page.ts b/src/common/Page.ts
index 4fae37357d3c2..d42418208f5c6 100644
--- a/src/common/Page.ts
+++ b/src/common/Page.ts
@@ -1360,21 +1360,25 @@ export class Page extends EventEmitter {
    */
   async exposeFunction(
     name: string,
-    puppeteerFunction: Function
+    puppeteerFunction: Function | { default: Function }
   ): Promise<void> {
     if (this._pageBindings.has(name))
       throw new Error(
         `Failed to add page binding with name ${name}: window['${name}'] already exists!`
       );
 
-    if (
-      typeof puppeteerFunction !== 'function' &&
-      typeof puppeteerFunction['default'] === 'function'
-    ) {
-      puppeteerFunction = puppeteerFunction['default'];
+    let exposedFunction: Function;
+    if (typeof puppeteerFunction === 'function') {
+      exposedFunction = puppeteerFunction;
+    } else if (typeof puppeteerFunction.default === 'function') {
+      exposedFunction = puppeteerFunction.default;
+    } else {
+      throw new Error(
+        `Failed to add page binding with name ${name}: ${puppeteerFunction} is not a function or a module with a default export.`
+      );
     }
 
-    this._pageBindings.set(name, puppeteerFunction);
+    this._pageBindings.set(name, exposedFunction);
 
     const expression = helper.pageBindingInitString('exposedFun', name);
     await this._client.send('Runtime.addBinding', { name: name });
diff --git a/test/page.spec.ts b/test/page.spec.ts
index 48eb23e72de6a..39304f84e6f39 100644
--- a/test/page.spec.ts
+++ b/test/page.spec.ts
@@ -1018,13 +1018,12 @@ describe('Page', function () {
     });
     it('should fallback to default export when passed a module object', async () => {
       const { page, server } = getTestState();
+      const moduleObject = {
+        default: function (a, b) {
+          return a * b;
+        },
+      };
       await page.goto(server.EMPTY_PAGE);
-      var moduleObject = {
-        default: function(a, b) {
-                  return a * b;
-                }
-              };
-      // @ts-expect-error
       await page.exposeFunction('compute', moduleObject);
       const result = await page.evaluate(async function () {
         return await globalThis.compute(9, 4);
@@ -1452,9 +1451,6 @@ describe('Page', function () {
         .catch((error_) => (error = error_));
       expect(error).toBeTruthy();
     });
-
-
-
   });
 
   describe('Page.addStyleTag', function () {