chore: enforce naming of errors in catch blocks (#5763)

.eslintrc.js

@@ -9,7 +9,8 @@ module.exports = {
 
     "plugins": [
         "mocha",
-        "@typescript-eslint"
+        "@typescript-eslint",
+        "unicorn"
     ],
 
     "rules": {
@@ -99,7 +100,10 @@ module.exports = {
         }],
 
         // ensure we don't have any it.only or describe.only in prod
-        "mocha/no-exclusive-tests": "error"
+        "mocha/no-exclusive-tests": "error",
+
+        // enforce the variable in a catch block is named error
+        "unicorn/catch-error-name": "error"
     },
     "overrides": [
         {

package.json

@@ -69,6 +69,7 @@
     "cross-env": "^5.0.5",
     "eslint": "^6.8.0",
     "eslint-plugin-mocha": "^6.3.0",
+    "eslint-plugin-unicorn": "^19.0.1",
     "esprima": "^4.0.0",
     "expect": "^25.2.7",
     "jpeg-js": "^0.3.7",

src/BrowserFetcher.ts

@@ -429,7 +429,7 @@ function installDMG(dmgPath: string, folderPath: string): Promise<void> {
     });
   }
 
-  return new Promise<void>(mountAndCopy).catch(err => { console.error(err); }).finally(unmount);
+  return new Promise<void>(mountAndCopy).catch(error => { console.error(error); }).finally(unmount);
 }
 
 function httpRequest(url: string, method: string, response: (x: http.IncomingMessage) => void): http.ClientRequest {

src/Coverage.ts

@@ -105,9 +105,9 @@ class JSCoverage {
       const response = await this._client.send('Debugger.getScriptSource', {scriptId: event.scriptId});
       this._scriptURLs.set(event.scriptId, event.url);
       this._scriptSources.set(event.scriptId, response.scriptSource);
-    } catch (e) {
+    } catch (error) {
       // This might happen if the page has already navigated away.
-      debugError(e);
+      debugError(error);
     }
   }
 
@@ -196,9 +196,9 @@ class CSSCoverage {
       const response = await this._client.send('CSS.getStyleSheetText', {styleSheetId: header.styleSheetId});
       this._stylesheetURLs.set(header.styleSheetId, header.sourceURL);
       this._stylesheetSources.set(header.styleSheetId, response.text);
-    } catch (e) {
+    } catch (error) {
       // This might happen if the page has already navigated away.
-      debugError(e);
+      debugError(error);
     }
   }
 

src/DOMWorld.js

@@ -579,8 +579,8 @@ class WaitTask {
     let error = null;
     try {
       success = await (await this._domWorld.executionContext()).evaluateHandle(waitForPredicatePageFunction, this._predicateBody, this._polling, this._timeout, ...this._args);
-    } catch (e) {
+    } catch (error_) {
-      error = e;
+      error = error_;
     }
 
     if (this._terminated || runCount !== this._runCount) {
@@ -592,7 +592,7 @@ class WaitTask {
     // Ignore timeouts in pageScript - we track timeouts ourselves.
     // If the frame's execution context has already changed, `frame.evaluate` will
     // throw an error - ignore this predicate run altogether.
-    if (!error && await this._domWorld.evaluate(s => !s, success).catch(e => true)) {
+    if (!error && await this._domWorld.evaluate(s => !s, success).catch(error_ => true)) {
       await success.dispose();
       return;
     }

src/ExecutionContext.ts

@@ -72,7 +72,7 @@ export class ExecutionContext {
     let functionText = pageFunction.toString();
     try {
       new Function('(' + functionText + ')');
-    } catch (e1) {
+    } catch (error) {
       // This means we might have a function shorthand. Try another
       // time prefixing 'function '.
       if (functionText.startsWith('async '))
@@ -81,7 +81,7 @@ export class ExecutionContext {
         functionText = 'function ' + functionText;
       try {
         new Function('(' + functionText  + ')');
-      } catch (e2) {
+      } catch (error) {
         // We tried hard to serialize, but there's a weird beast here.
         throw new Error('Passed function is not well-serializable!');
       }
@@ -96,10 +96,10 @@ export class ExecutionContext {
         awaitPromise: true,
         userGesture: true
       });
-    } catch (err) {
+    } catch (error) {
-      if (err instanceof TypeError && err.message.startsWith('Converting circular structure to JSON'))
+      if (error instanceof TypeError && error.message.startsWith('Converting circular structure to JSON'))
-        err.message += ' Are you passing a nested JSHandle?';
+        error.message += ' Are you passing a nested JSHandle?';
-      throw err;
+      throw error;
     }
     const {exceptionDetails, result: remoteObject} = await callFunctionOnPromise.catch(rewriteError);
     if (exceptionDetails)

src/Launcher.js

@@ -98,7 +98,7 @@ class BrowserRunner {
         if (this._tempDirectory) {
           removeFolderAsync(this._tempDirectory)
               .then(() => fulfill())
-              .catch(err => console.error(err));
+              .catch(error => console.error(error));
         } else {
           fulfill();
         }
@@ -819,9 +819,9 @@ function getWSEndpoint(browserURL) {
   request.on('error', reject);
   request.end();
 
-  return promise.catch(e => {
+  return promise.catch(error => {
-    e.message = `Failed to fetch browser webSocket url from ${endpointURL}: ` + e.message;
+    error.message = `Failed to fetch browser webSocket url from ${endpointURL}: ` + error.message;
-    throw e;
+    throw error;
   });
 }
 

src/Page.js

@@ -179,9 +179,9 @@ class Page extends EventEmitter {
     let callback;
     const promise = new Promise(x => callback = x);
     this._fileChooserInterceptors.add(callback);
-    return helper.waitWithTimeout(promise, 'waiting for file chooser', timeout).catch(e => {
+    return helper.waitWithTimeout(promise, 'waiting for file chooser', timeout).catch(error => {
       this._fileChooserInterceptors.delete(callback);
-      throw e;
+      throw error;
     });
   }
 
@@ -851,10 +851,10 @@ class Page extends EventEmitter {
   async emulateTimezone(timezoneId) {
     try {
       await this._client.send('Emulation.setTimezoneOverride', {timezoneId: timezoneId || ''});
-    } catch (exception) {
+    } catch (error) {
-      if (exception.message.includes('Invalid timezone'))
+      if (error.message.includes('Invalid timezone'))
         throw new Error(`Invalid timezone ID: ${timezoneId}`);
-      throw exception;
+      throw error;
     }
   }
 

src/helper.ts

@@ -90,12 +90,12 @@ function installAsyncStackHooks(classType: AnyClass): void {
         stack: ''
       };
       Error.captureStackTrace(syncStack);
-      return method.call(this, ...args).catch(e => {
+      return method.call(this, ...args).catch(error => {
         const stack = syncStack.stack.substring(syncStack.stack.indexOf('\n') + 1);
         const clientStack = stack.substring(stack.indexOf('\n'));
-        if (e instanceof Error && e.stack && !e.stack.includes(clientStack))
+        if (error instanceof Error && error.stack && !error.stack.includes(clientStack))
-          e.stack += '\n  -- ASYNC --\n' + stack;
+          error.stack += '\n  -- ASYNC --\n' + stack;
-        throw e;
+        throw error;
       });
     });
   }
@@ -149,9 +149,9 @@ async function waitForEvent<T extends any>(emitter: NodeJS.EventEmitter, eventNa
   const result = await Promise.race([promise, abortPromise]).then(r => {
     cleanup();
     return r;
-  }, e => {
+  }, error => {
     cleanup();
-    throw e;
+    throw error;
   });
   if (result instanceof Error)
     throw result;

test/CDPSession.spec.js

@@ -72,8 +72,8 @@ describeChromeOnly('Target.createCDPSession', function() {
     let error = null;
     try {
       await client.send('Runtime.evaluate', {expression: '3 + 1', returnByValue: true});
-    } catch (e) {
+    } catch (error_) {
-      error = e;
+      error = error_;
     }
     expect(error.message).toContain('Session closed.');
   });

test/browsercontext.spec.js

@@ -26,7 +26,7 @@ describe('BrowserContext', function() {
     const defaultContext = browser.browserContexts()[0];
     expect(defaultContext.isIncognito()).toBe(false);
     let error = null;
-    await defaultContext.close().catch(e => error = e);
+    await defaultContext.close().catch(error_ => error = error_);
     expect(browser.defaultBrowserContext()).toBe(defaultContext);
     expect(error.message).toContain('cannot be closed');
   });
@@ -104,7 +104,7 @@ describe('BrowserContext', function() {
     const {browser, server, puppeteer} = getTestState();
 
     const context = await browser.createIncognitoBrowserContext();
-    const error = await context.waitForTarget(target => target.url() === server.EMPTY_PAGE, {timeout: 1}).catch(e => e);
+    const error = await context.waitForTarget(target => target.url() === server.EMPTY_PAGE, {timeout: 1}).catch(error_ => error_);
     expect(error).toBeInstanceOf(puppeteer.errors.TimeoutError);
     await context.close();
   });

test/chromiumonly.spec.js

@@ -46,7 +46,7 @@ describeChromeOnly('Chromium-Specific Launcher tests', function() {
       const browserURL = 'http://127.0.0.1:21222';
 
       let error = null;
-      await puppeteer.connect({browserURL, browserWSEndpoint: originalBrowser.wsEndpoint()}).catch(e => error = e);
+      await puppeteer.connect({browserURL, browserWSEndpoint: originalBrowser.wsEndpoint()}).catch(error_ => error = error_);
       expect(error.message).toContain('Exactly one of browserWSEndpoint, browserURL or transport');
 
       originalBrowser.close();
@@ -60,7 +60,7 @@ describeChromeOnly('Chromium-Specific Launcher tests', function() {
       const browserURL = 'http://127.0.0.1:32333';
 
       let error = null;
-      await puppeteer.connect({browserURL}).catch(e => error = e);
+      await puppeteer.connect({browserURL}).catch(error_ => error = error_);
       expect(error.message).toContain('Failed to fetch browser webSocket url from');
       originalBrowser.close();
     });

test/click.spec.js

@@ -69,7 +69,7 @@ describe('Page.click', function() {
     await Promise.all([
       newPage.close(),
       newPage.mouse.click(1, 2),
-    ]).catch(e => {});
+    ]).catch(error => {});
   });
   it('should click the button after navigation ', async() => {
     const {page, server} = getTestState();
@@ -197,7 +197,7 @@ describe('Page.click', function() {
 
     await page.goto(server.PREFIX + '/input/button.html');
     let error = null;
-    await page.click('button.does-not-exist').catch(e => error = e);
+    await page.click('button.does-not-exist').catch(error_ => error = error_);
     expect(error.message).toBe('No node found for selector: button.does-not-exist');
   });
   // @see https://github.com/puppeteer/puppeteer/issues/161

test/cookies.spec.js

@@ -270,8 +270,8 @@ describe('Cookie specs', () => {
       let error = null;
       try {
         await page.setCookie({name: 'example-cookie', value: 'best'});
-      } catch (e) {
+      } catch (error_) {
-        error = e;
+        error = error_;
       }
       expect(error.message).toContain('At least one of the url and domain needs to be specified');
     });
@@ -285,8 +285,8 @@ describe('Cookie specs', () => {
             {name: 'example-cookie', value: 'best'},
             {url: 'about:blank', name: 'example-cookie-blank', value: 'best'}
         );
-      } catch (e) {
+      } catch (error_) {
-        error = e;
+        error = error_;
       }
       expect(error.message).toEqual(
           `Blank page can not have cookie "example-cookie-blank"`
@@ -299,8 +299,8 @@ describe('Cookie specs', () => {
       await page.goto('data:,Hello%2C%20World!');
       try {
         await page.setCookie({name: 'example-cookie', value: 'best'});
-      } catch (e) {
+      } catch (error_) {
-        error = e;
+        error = error_;
       }
       expect(error.message).toContain('At least one of the url and domain needs to be specified');
     });

test/elementhandle.spec.js

@@ -183,7 +183,7 @@ describe('ElementHandle specs', function() {
       await page.goto(server.PREFIX + '/input/button.html');
       const buttonTextNode = await page.evaluateHandle(() => document.querySelector('button').firstChild);
       let error = null;
-      await buttonTextNode.click().catch(err => error = err);
+      await buttonTextNode.click().catch(error_ => error = error_);
       expect(error.message).toBe('Node is not of type HTMLElement');
     });
     it('should throw for detached nodes', async() => {
@@ -193,7 +193,7 @@ describe('ElementHandle specs', function() {
       const button = await page.$('button');
       await page.evaluate(button => button.remove(), button);
       let error = null;
-      await button.click().catch(err => error = err);
+      await button.click().catch(error_ => error = error_);
       expect(error.message).toBe('Node is detached from document');
     });
     it('should throw for hidden nodes', async() => {
@@ -202,7 +202,7 @@ describe('ElementHandle specs', function() {
       await page.goto(server.PREFIX + '/input/button.html');
       const button = await page.$('button');
       await page.evaluate(button => button.style.display = 'none', button);
-      const error = await button.click().catch(err => err);
+      const error = await button.click().catch(error_ => error_);
       expect(error.message).toBe('Node is either not visible or not an HTMLElement');
     });
     it('should throw for recursively hidden nodes', async() => {
@@ -211,7 +211,7 @@ describe('ElementHandle specs', function() {
       await page.goto(server.PREFIX + '/input/button.html');
       const button = await page.$('button');
       await page.evaluate(button => button.parentElement.style.display = 'none', button);
-      const error = await button.click().catch(err => err);
+      const error = await button.click().catch(error_ => error_);
       expect(error.message).toBe('Node is either not visible or not an HTMLElement');
     });
     itFailsFirefox('should throw for <br> elements', async() => {
@@ -219,7 +219,7 @@ describe('ElementHandle specs', function() {
 
       await page.setContent('hello<br>goodbye');
       const br = await page.$('br');
-      const error = await br.click().catch(err => err);
+      const error = await br.click().catch(error_ => error_);
       expect(error.message).toBe('Node is either not visible or not an HTMLElement');
     });
   });

test/emulation.spec.js

@@ -148,7 +148,7 @@ describe('Emulation', () => {
       const {page} = getTestState();
 
       let error = null;
-      await page.emulateMedia('bad').catch(e => error = e);
+      await page.emulateMedia('bad').catch(error_ => error = error_);
       expect(error.message).toBe('Unsupported media type: bad');
     });
   });
@@ -173,7 +173,7 @@ describe('Emulation', () => {
       const {page} = getTestState();
 
       let error = null;
-      await page.emulateMediaType('bad').catch(e => error = e);
+      await page.emulateMediaType('bad').catch(error_ => error = error_);
       expect(error.message).toBe('Unsupported media type: bad');
     });
   });
@@ -213,7 +213,7 @@ describe('Emulation', () => {
       const {page} = getTestState();
 
       let error = null;
-      await page.emulateMediaFeatures([{name: 'bad', value: ''}]).catch(e => error = e);
+      await page.emulateMediaFeatures([{name: 'bad', value: ''}]).catch(error_ => error = error_);
       expect(error.message).toBe('Unsupported media feature: bad');
     });
   });
@@ -242,9 +242,9 @@ describe('Emulation', () => {
       const {page} = getTestState();
 
       let error = null;
-      await page.emulateTimezone('Foo/Bar').catch(e => error = e);
+      await page.emulateTimezone('Foo/Bar').catch(error_ => error = error_);
       expect(error.message).toBe('Invalid timezone ID: Foo/Bar');
-      await page.emulateTimezone('Baz/Qux').catch(e => error = e);
+      await page.emulateTimezone('Baz/Qux').catch(error_ => error = error_);
       expect(error.message).toBe('Invalid timezone ID: Baz/Qux');
     });
   });

test/evaluation.spec.js

@@ -115,7 +115,7 @@ describe('Evaluation specs', function() {
       await page.evaluate(() => {
         location.reload();
         return new Promise(() => {});
-      }).catch(e => error = e);
+      }).catch(error_ => error = error_);
       expect(error.message).toContain('Protocol error');
     });
     it('should await promise', async() => {
@@ -150,7 +150,7 @@ describe('Evaluation specs', function() {
       const {page} = getTestState();
 
       let error = null;
-      await page.evaluate(() => not_existing_object.property).catch(e => error = e);
+      await page.evaluate(() => not_existing_object.property).catch(error_ => error = error_);
       expect(error).toBeTruthy();
       expect(error.message).toContain('not_existing_object');
     });
@@ -158,7 +158,7 @@ describe('Evaluation specs', function() {
       const {page} = getTestState();
 
       let error = null;
-      await page.evaluate(() => { throw 'qwerty'; }).catch(e => error = e);
+      await page.evaluate(() => { throw 'qwerty'; }).catch(error_ => error = error_);
       expect(error).toBeTruthy();
       expect(error.message).toContain('qwerty');
     });
@@ -166,7 +166,7 @@ describe('Evaluation specs', function() {
       const {page} = getTestState();
 
       let error = null;
-      await page.evaluate(() => { throw 100500; }).catch(e => error = e);
+      await page.evaluate(() => { throw 100500; }).catch(error_ => error = error_);
       expect(error).toBeTruthy();
       expect(error.message).toContain('100500');
     });
@@ -239,10 +239,10 @@ describe('Evaluation specs', function() {
       const {page} = getTestState();
 
       const windowHandle = await page.evaluateHandle(() => window);
-      const errorText = await windowHandle.jsonValue().catch(e => e.message);
+      const errorText = await windowHandle.jsonValue().catch(error_ => error_.message);
       const error = await page.evaluate(errorText => {
         throw new Error(errorText);
-      }, errorText).catch(e => e);
+      }, errorText).catch(error_ => error_);
       expect(error.message).toContain(errorText);
     });
     it('should accept a string', async() => {
@@ -279,7 +279,7 @@ describe('Evaluation specs', function() {
       expect(element).toBeTruthy();
       await element.dispose();
       let error = null;
-      await page.evaluate(e => e.textContent, element).catch(e => error = e);
+      await page.evaluate(e => e.textContent, element).catch(error_ => error = error_);
       expect(error.message).toContain('JSHandle is disposed');
     });
     itFailsFirefox('should throw if elementHandles are from other frames', async() => {
@@ -288,7 +288,7 @@ describe('Evaluation specs', function() {
       await utils.attachFrame(page, 'frame1', server.EMPTY_PAGE);
       const bodyHandle = await page.frames()[1].$('body');
       let error = null;
-      await page.evaluate(body => body.innerHTML, bodyHandle).catch(e => error = e);
+      await page.evaluate(body => body.innerHTML, bodyHandle).catch(error_ => error = error_);
       expect(error).toBeTruthy();
       expect(error.message).toContain('JSHandles can be evaluated only in the context they were created');
     });
@@ -311,7 +311,7 @@ describe('Evaluation specs', function() {
         page.waitForNavigation(),
         executionContext.evaluate(() => window.location.reload())
       ]);
-      const error = await executionContext.evaluate(() => null).catch(e => e);
+      const error = await executionContext.evaluate(() => null).catch(error_ => error_);
       expect(error.message).toContain('navigation');
     });
     itFailsFirefox('should not throw an error when evaluation does a navigation', async() => {
@@ -336,7 +336,7 @@ describe('Evaluation specs', function() {
       let error = null;
       await page.evaluate(() => new Promise(() => {
         throw new Error('Error in promise');
-      })).catch(e => error = e);
+      })).catch(error_ => error = error_);
       expect(error.message).toContain('Error in promise');
     });
   });
@@ -362,7 +362,7 @@ describe('Evaluation specs', function() {
       expect(await page.evaluate(() => window.injected)).toBe(123);
 
       // Make sure CSP works.
-      await page.addScriptTag({content: 'window.e = 10;'}).catch(e => void e);
+      await page.addScriptTag({content: 'window.e = 10;'}).catch(error => void error);
       expect(await page.evaluate(() => window.e)).toBe(undefined);
     });
   });

test/frame.spec.js

@@ -69,7 +69,7 @@ describe('Frame specs', function() {
       const frame1 = await utils.attachFrame(page, 'frame1', server.EMPTY_PAGE);
       await utils.detachFrame(page, 'frame1');
       let error = null;
-      await frame1.evaluate(() => 7 * 8).catch(e => error = e);
+      await frame1.evaluate(() => 7 * 8).catch(error_ => error = error_);
       expect(error.message).toContain('Execution Context is not available in detached frame');
     });
   });

test/headful.spec.js

@@ -109,7 +109,7 @@ describeChromeOnly('headful tests', function() {
           const cookie = await headlessPage.evaluate(() => document.cookie);
           await headlessBrowser.close();
           // This might throw. See https://github.com/puppeteer/puppeteer/issues/2778
-          await rmAsync(userDataDir).catch(e => {});
+          await rmAsync(userDataDir).catch(error => {});
           expect(cookie).toBe('foo=true');
         });
     // TODO: Support OOOPIF. @see https://github.com/puppeteer/puppeteer/issues/2548

test/ignorehttpserrors.spec.js

@@ -92,7 +92,7 @@ describeFailsFirefox('ignoreHTTPSErrors', function() {
     const {httpsServer} = getTestState();
 
     let error = null;
-    const response = await page.goto(httpsServer.EMPTY_PAGE).catch(e => error = e);
+    const response = await page.goto(httpsServer.EMPTY_PAGE).catch(error_ => error = error_);
     expect(error).toBe(null);
     expect(response.ok()).toBe(true);
   });

test/input.spec.js

@@ -77,7 +77,7 @@ describe('input tests', function() {
       const {page, puppeteer} = getTestState();
 
       let error = null;
-      await page.waitForFileChooser({timeout: 1}).catch(e => error = e);
+      await page.waitForFileChooser({timeout: 1}).catch(error_ => error = error_);
       expect(error).toBeInstanceOf(puppeteer.errors.TimeoutError);
     });
     it('should respect default timeout when there is no custom timeout', async() => {
@@ -85,7 +85,7 @@ describe('input tests', function() {
 
       page.setDefaultTimeout(1);
       let error = null;
-      await page.waitForFileChooser().catch(e => error = e);
+      await page.waitForFileChooser().catch(error_ => error = error_);
       expect(error).toBeInstanceOf(puppeteer.errors.TimeoutError);
     });
     it('should prioritize exact timeout over default timeout', async() => {
@@ -93,7 +93,7 @@ describe('input tests', function() {
 
       page.setDefaultTimeout(0);
       let error = null;
-      await page.waitForFileChooser({timeout: 1}).catch(e => error = e);
+      await page.waitForFileChooser({timeout: 1}).catch(error_ => error = error_);
       expect(error).toBeInstanceOf(puppeteer.errors.TimeoutError);
     });
     it('should work with no timeout', async() => {
@@ -181,7 +181,7 @@ describe('input tests', function() {
       await chooser.accept([
         path.relative(process.cwd(), __dirname + '/assets/file-to-upload.txt'),
         path.relative(process.cwd(), __dirname + '/assets/pptr.png'),
-      ]).catch(e => error = e);
+      ]).catch(error_ => error = error_);
       expect(error).not.toBe(null);
     });
     it('should fail for non-existent files', async() => {
@@ -193,7 +193,7 @@ describe('input tests', function() {
         page.click('input'),
       ]);
       let error = null;
-      await chooser.accept(['file-does-not-exist.txt']).catch(e => error = e);
+      await chooser.accept(['file-does-not-exist.txt']).catch(error_ => error = error_);
       expect(error).not.toBe(null);
     });
     it('should fail when accepting file chooser twice', async() => {
@@ -206,7 +206,7 @@ describe('input tests', function() {
       ]);
       await fileChooser.accept([]);
       let error = null;
-      await fileChooser.accept([]).catch(e => error = e);
+      await fileChooser.accept([]).catch(error_ => error = error_);
       expect(error.message).toBe('Cannot accept FileChooser which is already handled!');
     });
   });
@@ -240,7 +240,7 @@ describe('input tests', function() {
       ]);
       await fileChooser.cancel();
       let error = null;
-      await fileChooser.cancel().catch(e => error = e);
+      await fileChooser.cancel().catch(error_ => error = error_);
       expect(error.message).toBe('Cannot cancel FileChooser which is already handled!');
     });
   });

test/jshandle.spec.js

@@ -50,7 +50,7 @@ describe('JSHandle', function() {
       await page.evaluateHandle(
           opts => opts.elem.querySelector('p'),
           {elem: aHandle}
-      ).catch(e => error = e);
+      ).catch(error_ => error = error_);
       expect(error.message).toContain('Are you passing a nested JSHandle?');
     });
     it('should accept object handle to unserializable value', async() => {
@@ -113,7 +113,7 @@ describe('JSHandle', function() {
 
       const windowHandle = await page.evaluateHandle('window');
       let error = null;
-      await windowHandle.jsonValue().catch(e => error = e);
+      await windowHandle.jsonValue().catch(error_ => error = error_);
       if (isChrome)
         expect(error.message).toContain('Object reference chain is too long');
       else

test/keyboard.spec.js

@@ -233,13 +233,13 @@ describe('Keyboard', function() {
   it('should throw on unknown keys', async() => {
     const {page} = getTestState();
 
-    let error = await page.keyboard.press('NotARealKey').catch(e => e);
+    let error = await page.keyboard.press('NotARealKey').catch(error_ => error_);
     expect(error.message).toBe('Unknown key: "NotARealKey"');
 
-    error = await page.keyboard.press('ё').catch(e => e);
+    error = await page.keyboard.press('ё').catch(error_ => error_);
     expect(error && error.message).toBe('Unknown key: "ё"');
 
-    error = await page.keyboard.press('😊').catch(e => e);
+    error = await page.keyboard.press('😊').catch(error_ => error_);
     expect(error && error.message).toBe('Unknown key: "😊"');
   });
   itFailsFirefox('should type emoji', async() => {

test/launcher.spec.js

@@ -102,7 +102,7 @@ describe('Launcher specs', function() {
         const browser = await puppeteer.launch(defaultBrowserOptions);
         const remote = await puppeteer.connect({browserWSEndpoint: browser.wsEndpoint()});
         const page = await remote.newPage();
-        const navigationPromise = page.goto(server.PREFIX + '/one-style.html', {timeout: 60000}).catch(e => e);
+        const navigationPromise = page.goto(server.PREFIX + '/one-style.html', {timeout: 60000}).catch(error_ => error_);
         await server.waitForRequest('/one-style.css');
         remote.disconnect();
         const error = await navigationPromise;
@@ -116,7 +116,7 @@ describe('Launcher specs', function() {
         const browser = await puppeteer.launch(defaultBrowserOptions);
         const remote = await puppeteer.connect({browserWSEndpoint: browser.wsEndpoint()});
         const page = await remote.newPage();
-        const watchdog = page.waitForSelector('div', {timeout: 60000}).catch(e => e);
+        const watchdog = page.waitForSelector('div', {timeout: 60000}).catch(error_ => error_);
         remote.disconnect();
         const error = await watchdog;
         expect(error.message).toContain('Protocol error');
@@ -131,8 +131,8 @@ describe('Launcher specs', function() {
         const remote = await puppeteer.connect({browserWSEndpoint: browser.wsEndpoint()});
         const newPage = await remote.newPage();
         const results = await Promise.all([
-          newPage.waitForRequest(server.EMPTY_PAGE).catch(e => e),
+          newPage.waitForRequest(server.EMPTY_PAGE).catch(error => error),
-          newPage.waitForResponse(server.EMPTY_PAGE).catch(e => e),
+          newPage.waitForResponse(server.EMPTY_PAGE).catch(error => error),
           browser.close()
         ]);
         for (let i = 0; i < 2; i++) {
@@ -149,7 +149,7 @@ describe('Launcher specs', function() {
         const browser = await puppeteer.launch(defaultBrowserOptions);
         const page = await browser.newPage();
         let error = null;
-        const neverResolves = page.evaluate(() => new Promise(r => {})).catch(e => error = e);
+        const neverResolves = page.evaluate(() => new Promise(r => {})).catch(error_ => error = error_);
         await browser.close();
         await neverResolves;
         expect(error.message).toContain('Protocol error');
@@ -159,7 +159,7 @@ describe('Launcher specs', function() {
 
         let waitError = null;
         const options = Object.assign({}, defaultBrowserOptions, {executablePath: 'random-invalid-path'});
-        await puppeteer.launch(options).catch(e => waitError = e);
+        await puppeteer.launch(options).catch(error => waitError = error);
         expect(waitError.message).toContain('Failed to launch');
       });
       it('userDataDir option', async() => {
@@ -174,7 +174,7 @@ describe('Launcher specs', function() {
         await browser.close();
         expect(fs.readdirSync(userDataDir).length).toBeGreaterThan(0);
         // This might throw. See https://github.com/puppeteer/puppeteer/issues/2778
-        await rmAsync(userDataDir).catch(e => {});
+        await rmAsync(userDataDir).catch(error => {});
       });
       it('userDataDir argument', async() => {
         const {isChrome, puppeteer, defaultBrowserOptions} = getTestState();
@@ -198,7 +198,7 @@ describe('Launcher specs', function() {
         await browser.close();
         expect(fs.readdirSync(userDataDir).length).toBeGreaterThan(0);
         // This might throw. See https://github.com/puppeteer/puppeteer/issues/2778
-        await rmAsync(userDataDir).catch(e => {});
+        await rmAsync(userDataDir).catch(error => {});
       });
       it('userDataDir option should restore state', async() => {
         const {server, puppeteer, defaultBrowserOptions} = getTestState();
@@ -217,7 +217,7 @@ describe('Launcher specs', function() {
         expect(await page2.evaluate(() => localStorage.hey)).toBe('hello');
         await browser2.close();
         // This might throw. See https://github.com/puppeteer/puppeteer/issues/2778
-        await rmAsync(userDataDir).catch(e => {});
+        await rmAsync(userDataDir).catch(error => {});
       });
       // This mysteriously fails on Windows on AppVeyor. See https://github.com/puppeteer/puppeteer/issues/4111
       xit('userDataDir option should restore cookies', async() => {
@@ -237,7 +237,7 @@ describe('Launcher specs', function() {
         expect(await page2.evaluate(() => document.cookie)).toBe('doSomethingOnlyOnce=true');
         await browser2.close();
         // This might throw. See https://github.com/puppeteer/puppeteer/issues/2778
-        await rmAsync(userDataDir).catch(e => {});
+        await rmAsync(userDataDir).catch(error => {});
       });
       it('should return the default arguments', async() => {
         const {isChrome, isFirefox, puppeteer} = getTestState();
@@ -429,7 +429,7 @@ describe('Launcher specs', function() {
         let error = null;
         const [serverRequest, response] = await Promise.all([
           httpsServer.waitForRequest('/empty.html'),
-          page.goto(httpsServer.EMPTY_PAGE).catch(e => error = e)
+          page.goto(httpsServer.EMPTY_PAGE).catch(error_ => error = error_)
         ]);
         expect(error).toBe(null);
         expect(response.ok()).toBe(true);

test/navigation.spec.js

@@ -75,7 +75,7 @@ describe('navigation', function() {
         res.end();
       });
       let error = null;
-      await page.goto(server.EMPTY_PAGE).catch(e => error = e);
+      await page.goto(server.EMPTY_PAGE).catch(error_ => error = error_);
       expect(error).not.toBe(null);
       if (isChrome)
         expect(error.message).toContain('net::ERR_ABORTED');
@@ -114,7 +114,7 @@ describe('navigation', function() {
       const {page, isChrome} = getTestState();
 
       let error = null;
-      await page.goto('asdfasdf').catch(e => error = e);
+      await page.goto('asdfasdf').catch(error_ => error = error_);
       if (isChrome)
         expect(error.message).toContain('Cannot navigate to invalid URL');
       else
@@ -129,7 +129,7 @@ describe('navigation', function() {
       page.on('requestfinished', request => expect(request).toBeTruthy());
       page.on('requestfailed', request => expect(request).toBeTruthy());
       let error = null;
-      await page.goto(httpsServer.EMPTY_PAGE).catch(e => error = e);
+      await page.goto(httpsServer.EMPTY_PAGE).catch(error_ => error = error_);
       if (isChrome)
         expect(error.message).toContain('net::ERR_CERT_AUTHORITY_INVALID');
       else
@@ -141,7 +141,7 @@ describe('navigation', function() {
       server.setRedirect('/redirect/1.html', '/redirect/2.html');
       server.setRedirect('/redirect/2.html', '/empty.html');
       let error = null;
-      await page.goto(httpsServer.PREFIX + '/redirect/1.html').catch(e => error = e);
+      await page.goto(httpsServer.PREFIX + '/redirect/1.html').catch(error_ => error = error_);
       if (isChrome)
         expect(error.message).toContain('net::ERR_CERT_AUTHORITY_INVALID');
       else
@@ -151,14 +151,14 @@ describe('navigation', function() {
       const {page, server} = getTestState();
 
       let error = null;
-      await page.goto(server.EMPTY_PAGE, {waitUntil: 'networkidle'}).catch(err => error = err);
+      await page.goto(server.EMPTY_PAGE, {waitUntil: 'networkidle'}).catch(error_ => error = error_);
       expect(error.message).toContain('"networkidle" option is no longer supported');
     });
     itFailsFirefox('should fail when main resources failed to load', async() => {
       const {page, isChrome} = getTestState();
 
       let error = null;
-      await page.goto('http://localhost:44123/non-existing-url').catch(e => error = e);
+      await page.goto('http://localhost:44123/non-existing-url').catch(error_ => error = error_);
       if (isChrome)
         expect(error.message).toContain('net::ERR_CONNECTION_REFUSED');
       else
@@ -170,7 +170,7 @@ describe('navigation', function() {
       // Hang for request to the empty.html
       server.setRoute('/empty.html', (req, res) => { });
       let error = null;
-      await page.goto(server.PREFIX + '/empty.html', {timeout: 1}).catch(e => error = e);
+      await page.goto(server.PREFIX + '/empty.html', {timeout: 1}).catch(error_ => error = error_);
       expect(error.message).toContain('Navigation timeout of 1 ms exceeded');
       expect(error).toBeInstanceOf(puppeteer.errors.TimeoutError);
     });
@@ -181,7 +181,7 @@ describe('navigation', function() {
       server.setRoute('/empty.html', (req, res) => { });
       let error = null;
       page.setDefaultNavigationTimeout(1);
-      await page.goto(server.PREFIX + '/empty.html').catch(e => error = e);
+      await page.goto(server.PREFIX + '/empty.html').catch(error_ => error = error_);
       expect(error.message).toContain('Navigation timeout of 1 ms exceeded');
       expect(error).toBeInstanceOf(puppeteer.errors.TimeoutError);
     });
@@ -192,7 +192,7 @@ describe('navigation', function() {
       server.setRoute('/empty.html', (req, res) => { });
       let error = null;
       page.setDefaultTimeout(1);
-      await page.goto(server.PREFIX + '/empty.html').catch(e => error = e);
+      await page.goto(server.PREFIX + '/empty.html').catch(error_ => error = error_);
       expect(error.message).toContain('Navigation timeout of 1 ms exceeded');
       expect(error).toBeInstanceOf(puppeteer.errors.TimeoutError);
     });
@@ -204,7 +204,7 @@ describe('navigation', function() {
       let error = null;
       page.setDefaultTimeout(0);
       page.setDefaultNavigationTimeout(1);
-      await page.goto(server.PREFIX + '/empty.html').catch(e => error = e);
+      await page.goto(server.PREFIX + '/empty.html').catch(error_ => error = error_);
       expect(error.message).toContain('Navigation timeout of 1 ms exceeded');
       expect(error).toBeInstanceOf(puppeteer.errors.TimeoutError);
     });
@@ -214,7 +214,7 @@ describe('navigation', function() {
       let error = null;
       let loaded = false;
       page.once('load', () => loaded = true);
-      await page.goto(server.PREFIX + '/grid.html', {timeout: 0, waitUntil: ['load']}).catch(e => error = e);
+      await page.goto(server.PREFIX + '/grid.html', {timeout: 0, waitUntil: ['load']}).catch(error_ => error = error_);
       expect(error).toBe(null);
       expect(loaded).toBe(true);
     });
@@ -324,7 +324,7 @@ describe('navigation', function() {
       const warningHandler = w => warning = w;
       process.on('warning', warningHandler);
       for (let i = 0; i < 20; ++i)
-        await page.goto('asdf').catch(e => {/* swallow navigation error */});
+        await page.goto('asdf').catch(error => {/* swallow navigation error */});
       process.removeListener('warning', warningHandler);
       expect(warning).toBe(null);
     });
@@ -378,8 +378,8 @@ describe('navigation', function() {
       let error = null;
       try {
         await page.goto(url);
-      } catch (e) {
+      } catch (error_) {
-        error = e;
+        error = error_;
       }
       expect(error.message).toContain(url);
     });
@@ -581,7 +581,7 @@ describe('navigation', function() {
       await page.goto(server.PREFIX + '/frames/one-frame.html');
 
       server.setRoute('/empty.html', () => {});
-      const navigationPromise = page.frames()[1].goto(server.EMPTY_PAGE).catch(e => e);
+      const navigationPromise = page.frames()[1].goto(server.EMPTY_PAGE).catch(error_ => error_);
       await server.waitForRequest('/empty.html');
 
       await page.$eval('iframe', frame => frame.remove());
@@ -642,7 +642,7 @@ describe('navigation', function() {
 
       server.setRoute('/empty.html', () => {});
       let error = null;
-      const navigationPromise = frame.waitForNavigation().catch(e => error = e);
+      const navigationPromise = frame.waitForNavigation().catch(error_ => error = error_);
       await Promise.all([
         server.waitForRequest('/empty.html'),
         frame.evaluate(() => window.location = '/empty.html')

test/network.spec.js

@@ -211,7 +211,7 @@ describe('network', function() {
       const redirected = redirectChain[0].response();
       expect(redirected.status()).toBe(302);
       let error = null;
-      await redirected.text().catch(e => error = e);
+      await redirected.text().catch(error_ => error = error_);
       expect(error.message).toContain('Response body is unavailable for redirect responses');
     });
     it('should wait until response completes', async() => {
@@ -458,8 +458,8 @@ describe('network', function() {
       let error = null;
       try {
         await page.setExtraHTTPHeaders({'foo': 1});
-      } catch (e) {
+      } catch (error_) {
-        error = e;
+        error = error_;
       }
       expect(error.message).toBe('Expected value of header "foo" to be String, but "number" is found.');
     });

test/page.spec.js

@@ -30,7 +30,7 @@ describe('Page', function() {
       const newPage = await context.newPage();
       let error = null;
       await Promise.all([
-        newPage.evaluate(() => new Promise(r => {})).catch(e => error = e),
+        newPage.evaluate(() => new Promise(r => {})).catch(error_ => error = error_),
         newPage.close(),
       ]);
       expect(error.message).toContain('Protocol error');
@@ -85,8 +85,8 @@ describe('Page', function() {
 
       const newPage = await context.newPage();
       const results = await Promise.all([
-        newPage.waitForRequest(server.EMPTY_PAGE).catch(e => e),
+        newPage.waitForRequest(server.EMPTY_PAGE).catch(error => error),
-        newPage.waitForResponse(server.EMPTY_PAGE).catch(e => e),
+        newPage.waitForResponse(server.EMPTY_PAGE).catch(error => error),
         newPage.close()
       ]);
       for (let i = 0; i < 2; i++) {
@@ -117,7 +117,7 @@ describe('Page', function() {
         res.end();
       });
       let error = null;
-      await page.goto(server.EMPTY_PAGE).catch(e => error = e);
+      await page.goto(server.EMPTY_PAGE).catch(error_ => error = error_);
       expect(error).not.toBe(null);
       expect(error.stack).toContain(__filename);
     });
@@ -129,7 +129,7 @@ describe('Page', function() {
 
       let error = null;
       page.on('error', err => error = err);
-      page.goto('chrome://crash').catch(e => {});
+      page.goto('chrome://crash').catch(error_ => {});
       await waitEvent(page, 'error');
       expect(error.message).toBe('Page crashed!');
     });
@@ -217,7 +217,7 @@ describe('Page', function() {
 
       await page.goto(server.EMPTY_PAGE);
       let error = null;
-      await context.overridePermissions(server.EMPTY_PAGE, ['foo']).catch(e => error = e);
+      await context.overridePermissions(server.EMPTY_PAGE, ['foo']).catch(error_ => error = error_);
       expect(error.message).toBe('Unknown permission: foo');
     });
     itFailsFirefox('should grant permission when listed', async() => {
@@ -301,8 +301,8 @@ describe('Page', function() {
       let error = null;
       try {
         await page.setGeolocation({longitude: 200, latitude: 10});
-      } catch (e) {
+      } catch (error_) {
-        error = e;
+        error = error_;
       }
       expect(error.message).toContain('Invalid longitude "200"');
     });
@@ -314,7 +314,7 @@ describe('Page', function() {
 
       await page.setOfflineMode(true);
       let error = null;
-      await page.goto(server.EMPTY_PAGE).catch(e => error = e);
+      await page.goto(server.EMPTY_PAGE).catch(error_ => error = error_);
       expect(error).toBeTruthy();
       await page.setOfflineMode(false);
       const response = await page.reload();
@@ -361,7 +361,7 @@ describe('Page', function() {
       const prototypeHandle = await page.evaluateHandle(() => HTMLBodyElement.prototype);
       await prototypeHandle.dispose();
       let error = null;
-      await page.queryObjects(prototypeHandle).catch(e => error = e);
+      await page.queryObjects(prototypeHandle).catch(error_ => error = error_);
       expect(error.message).toBe('Prototype JSHandle is disposed!');
     });
     it('should fail primitive values as prototypes', async() => {
@@ -369,7 +369,7 @@ describe('Page', function() {
 
       const prototypeHandle = await page.evaluateHandle(() => 42);
       let error = null;
-      await page.queryObjects(prototypeHandle).catch(e => error = e);
+      await page.queryObjects(prototypeHandle).catch(error_ => error = error_);
       expect(error.message).toBe('Prototype JSHandle must not be referencing primitive value');
     });
   });
@@ -435,7 +435,7 @@ describe('Page', function() {
       await page.goto('about:blank');
       const [message] = await Promise.all([
         waitEvent(page, 'console'),
-        page.evaluate(async url => fetch(url).catch(e => {}), server.EMPTY_PAGE)
+        page.evaluate(async url => fetch(url).catch(error => {}), server.EMPTY_PAGE)
       ]);
       expect(message.text()).toContain('Access-Control-Allow-Origin');
       if (isChrome)
@@ -582,7 +582,7 @@ describe('Page', function() {
       const {page, puppeteer} = getTestState();
 
       let error = null;
-      await page.waitForRequest(() => false, {timeout: 1}).catch(e => error = e);
+      await page.waitForRequest(() => false, {timeout: 1}).catch(error_ => error = error_);
       expect(error).toBeInstanceOf(puppeteer.errors.TimeoutError);
     });
     it('should respect default timeout', async() => {
@@ -590,7 +590,7 @@ describe('Page', function() {
 
       let error = null;
       page.setDefaultTimeout(1);
-      await page.waitForRequest(() => false).catch(e => error = e);
+      await page.waitForRequest(() => false).catch(error_ => error = error_);
       expect(error).toBeInstanceOf(puppeteer.errors.TimeoutError);
     });
     it('should work with no timeout', async() => {
@@ -628,7 +628,7 @@ describe('Page', function() {
       const {page, puppeteer} = getTestState();
 
       let error = null;
-      await page.waitForResponse(() => false, {timeout: 1}).catch(e => error = e);
+      await page.waitForResponse(() => false, {timeout: 1}).catch(error_ => error = error_);
       expect(error).toBeInstanceOf(puppeteer.errors.TimeoutError);
     });
     it('should respect default timeout', async() => {
@@ -636,7 +636,7 @@ describe('Page', function() {
 
       let error = null;
       page.setDefaultTimeout(1);
-      await page.waitForResponse(() => false).catch(e => error = e);
+      await page.waitForResponse(() => false).catch(error_ => error = error_);
       expect(error).toBeInstanceOf(puppeteer.errors.TimeoutError);
     });
     itFailsFirefox('should work with predicate', async() => {
@@ -690,8 +690,8 @@ describe('Page', function() {
       const {message, stack} = await page.evaluate(async() => {
         try {
           await woof();
-        } catch (e) {
+        } catch (error) {
-          return {message: e.message, stack: e.stack};
+          return {message: error.message, stack: error.stack};
         }
       });
       expect(message).toBe('WOOF WOOF');
@@ -706,8 +706,8 @@ describe('Page', function() {
       const thrown = await page.evaluate(async() => {
         try {
           await woof();
-        } catch (e) {
+        } catch (error) {
-          return e;
+          return error;
         }
       });
       expect(thrown).toBe(null);
@@ -867,7 +867,7 @@ describe('Page', function() {
       // stall for image
       server.setRoute(imgPath, (req, res) => {});
       let error = null;
-      await page.setContent(`<img src="${server.PREFIX + imgPath}"></img>`, {timeout: 1}).catch(e => error = e);
+      await page.setContent(`<img src="${server.PREFIX + imgPath}"></img>`, {timeout: 1}).catch(error_ => error = error_);
       expect(error).toBeInstanceOf(puppeteer.errors.TimeoutError);
     });
     it('should respect default navigation timeout', async() => {
@@ -878,7 +878,7 @@ describe('Page', function() {
       // stall for image
       server.setRoute(imgPath, (req, res) => {});
       let error = null;
-      await page.setContent(`<img src="${server.PREFIX + imgPath}"></img>`).catch(e => error = e);
+      await page.setContent(`<img src="${server.PREFIX + imgPath}"></img>`).catch(error_ => error = error_);
       expect(error).toBeInstanceOf(puppeteer.errors.TimeoutError);
     });
     it('should await resources to load', async() => {
@@ -932,7 +932,7 @@ describe('Page', function() {
 
       // Make sure CSP prohibits addScriptTag.
       await page.goto(server.PREFIX + '/csp.html');
-      await page.addScriptTag({content: 'window.__injected = 42;'}).catch(e => void e);
+      await page.addScriptTag({content: 'window.__injected = 42;'}).catch(error => void error);
       expect(await page.evaluate(() => window.__injected)).toBe(undefined);
 
       // By-pass CSP and try one more time.
@@ -948,7 +948,7 @@ describe('Page', function() {
       // Make sure CSP prohibits addScriptTag.
       server.setCSP('/empty.html', 'default-src "self"');
       await page.goto(server.EMPTY_PAGE);
-      await page.addScriptTag({content: 'window.__injected = 42;'}).catch(e => void e);
+      await page.addScriptTag({content: 'window.__injected = 42;'}).catch(error => void error);
       expect(await page.evaluate(() => window.__injected)).toBe(undefined);
 
       // By-pass CSP and try one more time.
@@ -977,7 +977,7 @@ describe('Page', function() {
       {
         // Make sure CSP prohibits addScriptTag in an iframe.
         const frame = await utils.attachFrame(page, 'frame1', server.PREFIX + '/csp.html');
-        await frame.addScriptTag({content: 'window.__injected = 42;'}).catch(e => void e);
+        await frame.addScriptTag({content: 'window.__injected = 42;'}).catch(error => void error);
         expect(await frame.evaluate(() => window.__injected)).toBe(undefined);
       }
 
@@ -987,7 +987,7 @@ describe('Page', function() {
 
       {
         const frame = await utils.attachFrame(page, 'frame1', server.PREFIX + '/csp.html');
-        await frame.addScriptTag({content: 'window.__injected = 42;'}).catch(e => void e);
+        await frame.addScriptTag({content: 'window.__injected = 42;'}).catch(error => void error);
         expect(await frame.evaluate(() => window.__injected)).toBe(42);
       }
     });
@@ -1000,8 +1000,8 @@ describe('Page', function() {
       let error = null;
       try {
         await page.addScriptTag('/injectedfile.js');
-      } catch (e) {
+      } catch (error_) {
-        error = e;
+        error = error_;
       }
       expect(error.message).toBe('Provide an object with a `url`, `path` or `content` property');
     });
@@ -1048,8 +1048,8 @@ describe('Page', function() {
       let error = null;
       try {
         await page.addScriptTag({url: '/nonexistfile.js'});
-      } catch (e) {
+      } catch (error_) {
-        error = e;
+        error = error_;
       }
       expect(error.message).toBe('Loading script from /nonexistfile.js failed');
     });
@@ -1087,7 +1087,7 @@ describe('Page', function() {
 
       await page.goto(server.PREFIX + '/csp.html');
       let error = null;
-      await page.addScriptTag({content: 'window.__injected = 35;'}).catch(e => error = e);
+      await page.addScriptTag({content: 'window.__injected = 35;'}).catch(error_ => error = error_);
       expect(error).toBeTruthy();
     });
 
@@ -1096,7 +1096,7 @@ describe('Page', function() {
 
       await page.goto(server.PREFIX + '/csp.html');
       let error = null;
-      await page.addScriptTag({url: server.CROSS_PROCESS_PREFIX + '/injectedfile.js'}).catch(e => error = e);
+      await page.addScriptTag({url: server.CROSS_PROCESS_PREFIX + '/injectedfile.js'}).catch(error_ => error = error_);
       expect(error).toBeTruthy();
     });
   });
@@ -1108,8 +1108,8 @@ describe('Page', function() {
       let error = null;
       try {
         await page.addStyleTag('/injectedstyle.css');
-      } catch (e) {
+      } catch (error_) {
-        error = e;
+        error = error_;
       }
       expect(error.message).toBe('Provide an object with a `url`, `path` or `content` property');
     });
@@ -1130,8 +1130,8 @@ describe('Page', function() {
       let error = null;
       try {
         await page.addStyleTag({url: '/nonexistfile.js'});
-      } catch (e) {
+      } catch (error_) {
-        error = e;
+        error = error_;
       }
       expect(error.message).toBe('Loading style from /nonexistfile.js failed');
     });
@@ -1169,7 +1169,7 @@ describe('Page', function() {
 
       await page.goto(server.PREFIX + '/csp.html');
       let error = null;
-      await page.addStyleTag({content: 'body { background-color: green; }'}).catch(e => error = e);
+      await page.addStyleTag({content: 'body { background-color: green; }'}).catch(error_ => error = error_);
       expect(error).toBeTruthy();
     });
 
@@ -1178,7 +1178,7 @@ describe('Page', function() {
 
       await page.goto(server.PREFIX + '/csp.html');
       let error = null;
-      await page.addStyleTag({url: server.CROSS_PROCESS_PREFIX + '/injectedstyle.css'}).catch(e => error = e);
+      await page.addStyleTag({url: server.CROSS_PROCESS_PREFIX + '/injectedstyle.css'}).catch(error_ => error = error_);
       expect(error).toBeTruthy();
     });
   });
@@ -1200,7 +1200,7 @@ describe('Page', function() {
       await page.setJavaScriptEnabled(false);
       await page.goto('data:text/html, <script>var something = "forbidden"</script>');
       let error = null;
-      await page.evaluate('something').catch(e => error = e);
+      await page.evaluate('something').catch(error_ => error = error_);
       expect(error.message).toContain('something is not defined');
 
       await page.setJavaScriptEnabled(true);
@@ -1317,7 +1317,7 @@ describe('Page', function() {
 
       let error = null;
       await page.goto(server.PREFIX + '/input/select.html');
-      await page.select('body', '').catch(e => error = e);
+      await page.select('body', '').catch(error_ => error = error_);
       expect(error.message).toContain('Element is not a <select> element.');
     });
     it('should return [] on no matched values', async() => {
@@ -1373,8 +1373,8 @@ describe('Page', function() {
       let error = null;
       try {
         await page.select('select', 12);
-      } catch (e) {
+      } catch (error_) {
-        error = e;
+        error = error_;
       }
       expect(error.message).toContain('Values must be strings');
     });

test/queryselector.spec.js

@@ -46,7 +46,7 @@ describe('querySelector', function() {
       const {page} = getTestState();
 
       let error = null;
-      await page.$eval('section', e => e.id).catch(e => error = e);
+      await page.$eval('section', e => e.id).catch(error_ => error = error_);
       expect(error.message).toContain('failed to find element matching selector "section"');
     });
   });

test/requestinterception.spec.js

@@ -202,7 +202,7 @@ describe('request interception', function() {
       });
       let failedRequest = null;
       page.on('requestfailed', request => failedRequest = request);
-      await page.goto(server.EMPTY_PAGE).catch(e => {});
+      await page.goto(server.EMPTY_PAGE).catch(error => {});
       expect(failedRequest).toBeTruthy();
       expect(failedRequest.failure().errorText).toBe('net::ERR_INTERNET_DISCONNECTED');
     });
@@ -226,7 +226,7 @@ describe('request interception', function() {
       await page.setRequestInterception(true);
       page.on('request', request => request.abort());
       let error = null;
-      await page.goto(server.EMPTY_PAGE).catch(e => error = e);
+      await page.goto(server.EMPTY_PAGE).catch(error_ => error = error_);
       expect(error).toBeTruthy();
       if (isChrome)
         expect(error.message).toContain('net::ERR_FAILED');
@@ -305,8 +305,8 @@ describe('request interception', function() {
       const result = await page.evaluate(async() => {
         try {
           await fetch('/non-existing.json');
-        } catch (e) {
+        } catch (error) {
-          return e.message;
+          return error.message;
         }
       });
       if (isChrome)
@@ -333,9 +333,9 @@ describe('request interception', function() {
         spinner = !spinner;
       });
       const results = await page.evaluate(() => Promise.all([
-        fetch('/zzz').then(response => response.text()).catch(e => 'FAILED'),
+        fetch('/zzz').then(response => response.text()).catch(error => 'FAILED'),
-        fetch('/zzz').then(response => response.text()).catch(e => 'FAILED'),
+        fetch('/zzz').then(response => response.text()).catch(error => 'FAILED'),
-        fetch('/zzz').then(response => response.text()).catch(e => 'FAILED'),
+        fetch('/zzz').then(response => response.text()).catch(error => 'FAILED'),
       ]));
       expect(results).toEqual(['11', 'FAILED', '22']);
     });
@@ -433,7 +433,7 @@ describe('request interception', function() {
       // Delete frame to cause request to be canceled.
       await page.$eval('iframe', frame => frame.remove());
       let error = null;
-      await request.continue().catch(e => error = e);
+      await request.continue().catch(error_ => error = error_);
       expect(error).toBe(null);
     });
     it('should throw if interception is not enabled', async() => {
@@ -443,8 +443,8 @@ describe('request interception', function() {
       page.on('request', async request => {
         try {
           await request.continue();
-        } catch (e) {
+        } catch (error_) {
-          error = e;
+          error = error_;
         }
       });
       await page.goto(server.EMPTY_PAGE);

test/screenshot.spec.js

@@ -257,7 +257,7 @@ describe('Screenshots', function() {
 
       await page.setContent('<div style="width: 50px; height: 0"></div>');
       const div = await page.$('div');
-      const error = await div.screenshot().catch(e => e);
+      const error = await div.screenshot().catch(error_ => error_);
       expect(error.message).toBe('Node has 0 height.');
     });
     itFailsFirefox('should work for an element with fractional dimensions', async() => {

test/target.spec.js

@@ -202,7 +202,7 @@ describe('Target', function() {
       let error = null;
       await browser.waitForTarget(target => target.url() === server.EMPTY_PAGE, {
         timeout: 1
-      }).catch(e => error = e);
+      }).catch(error_ => error = error_);
       expect(error).toBeInstanceOf(puppeteer.errors.TimeoutError);
     });
   });

test/tracing.spec.js

@@ -64,7 +64,7 @@ describeChromeOnly('Tracing', function() {
     await page.tracing.start({path: outputFile});
     const newPage = await browser.newPage();
     let error = null;
-    await newPage.tracing.start({path: outputFile}).catch(e => error = e);
+    await newPage.tracing.start({path: outputFile}).catch(error_ => error = error_);
     await newPage.close();
     expect(error).toBeTruthy();
     await page.tracing.stop();

test/waittask.spec.js

@@ -51,7 +51,7 @@ describe('waittask specs', function() {
 
       await page.setContent(`<div>some text</div>`);
       let error = null;
-      await page.waitFor('/html/body/div').catch(e => error = e);
+      await page.waitFor('/html/body/div').catch(error_ => error = error_);
       expect(error).toBeTruthy();
     });
     it('should timeout', async() => {
@@ -82,7 +82,7 @@ describe('waittask specs', function() {
       const {page} = getTestState();
 
       let error = null;
-      await page.waitFor({foo: 'bar'}).catch(e => error = e);
+      await page.waitFor({foo: 'bar'}).catch(error_ => error = error_);
       expect(error.message).toContain('Unsupported target type');
     });
     it('should wait for predicate with arguments', async() => {
@@ -149,7 +149,7 @@ describe('waittask specs', function() {
       await page.goto(server.EMPTY_PAGE);
       let error = null;
       await Promise.all([
-        page.waitForFunction(() => window.__FOO === 'hit', {polling: 'raf'}).catch(e => error = e),
+        page.waitForFunction(() => window.__FOO === 'hit', {polling: 'raf'}).catch(error_ => error = error_),
         page.evaluate(() => window.__FOO = 'hit')
       ]);
       expect(error).toBe(null);
@@ -160,8 +160,8 @@ describe('waittask specs', function() {
       let error = null;
       try {
         await page.waitForFunction(() => !!document.body, {polling: 'unknown'});
-      } catch (e) {
+      } catch (error_) {
-        error = e;
+        error = error_;
       }
       expect(error).toBeTruthy();
       expect(error.message).toContain('polling');
@@ -172,8 +172,8 @@ describe('waittask specs', function() {
       let error = null;
       try {
         await page.waitForFunction(() => !!document.body, {polling: -10});
-      } catch (e) {
+      } catch (error_) {
-        error = e;
+        error = error_;
       }
       expect(error).toBeTruthy();
       expect(error.message).toContain('Cannot poll with non-positive interval');
@@ -203,7 +203,7 @@ describe('waittask specs', function() {
       const {page, puppeteer} = getTestState();
 
       let error = null;
-      await page.waitForFunction('false', {timeout: 10}).catch(e => error = e);
+      await page.waitForFunction('false', {timeout: 10}).catch(error_ => error = error_);
       expect(error).toBeTruthy();
       expect(error.message).toContain('waiting for function failed: timeout');
       expect(error).toBeInstanceOf(puppeteer.errors.TimeoutError);
@@ -213,7 +213,7 @@ describe('waittask specs', function() {
 
       page.setDefaultTimeout(1);
       let error = null;
-      await page.waitForFunction('false').catch(e => error = e);
+      await page.waitForFunction('false').catch(error_ => error = error_);
       expect(error).toBeInstanceOf(puppeteer.errors.TimeoutError);
       expect(error.message).toContain('waiting for function failed: timeout');
     });
@@ -334,7 +334,7 @@ describe('waittask specs', function() {
       await utils.attachFrame(page, 'frame1', server.EMPTY_PAGE);
       const frame = page.frames()[1];
       let waitError = null;
-      const waitPromise = frame.waitForSelector('.box').catch(e => waitError = e);
+      const waitPromise = frame.waitForSelector('.box').catch(error => waitError = error);
       await utils.detachFrame(page, 'frame1');
       await waitPromise;
       expect(waitError).toBeTruthy();
@@ -425,7 +425,7 @@ describe('waittask specs', function() {
       const {page, puppeteer} = getTestState();
 
       let error = null;
-      await page.waitForSelector('div', {timeout: 10}).catch(e => error = e);
+      await page.waitForSelector('div', {timeout: 10}).catch(error_ => error = error_);
       expect(error).toBeTruthy();
       expect(error.message).toContain('waiting for selector "div" failed: timeout');
       expect(error).toBeInstanceOf(puppeteer.errors.TimeoutError);
@@ -435,7 +435,7 @@ describe('waittask specs', function() {
 
       await page.setContent(`<div></div>`);
       let error = null;
-      await page.waitForSelector('div', {hidden: true, timeout: 10}).catch(e => error = e);
+      await page.waitForSelector('div', {hidden: true, timeout: 10}).catch(error_ => error = error_);
       expect(error).toBeTruthy();
       expect(error.message).toContain('waiting for selector "div" to be hidden failed: timeout');
     });
@@ -461,7 +461,7 @@ describe('waittask specs', function() {
       const {page} = getTestState();
 
       let error;
-      await page.waitForSelector('.zombo', {timeout: 10}).catch(e => error = e);
+      await page.waitForSelector('.zombo', {timeout: 10}).catch(error_ => error = error_);
       expect(error.stack).toContain('waittask.spec.js');
     });
   });
@@ -480,7 +480,7 @@ describe('waittask specs', function() {
       const {page, puppeteer} = getTestState();
 
       let error = null;
-      await page.waitForXPath('//div', {timeout: 10}).catch(e => error = e);
+      await page.waitForXPath('//div', {timeout: 10}).catch(error_ => error = error_);
       expect(error).toBeTruthy();
       expect(error.message).toContain('waiting for XPath "//div" failed: timeout');
       expect(error).toBeInstanceOf(puppeteer.errors.TimeoutError);
@@ -504,7 +504,7 @@ describe('waittask specs', function() {
       await utils.attachFrame(page, 'frame1', server.EMPTY_PAGE);
       const frame = page.frames()[1];
       let waitError = null;
-      const waitPromise = frame.waitForXPath('//*[@class="box"]').catch(e => waitError = e);
+      const waitPromise = frame.waitForXPath('//*[@class="box"]').catch(error => waitError = error);
       await utils.detachFrame(page, 'frame1');
       await waitPromise;
       expect(waitError).toBeTruthy();

typescript-if-required.js

@@ -37,8 +37,8 @@ const fileExists = async filePath => fsAccess(filePath).then(() => true).catch((
  * place.
  */
 async function compileTypeScript() {
-  return exec('npm run tsc').catch(err => {
+  return exec('npm run tsc').catch(error => {
-    console.error('Error running TypeScript', err);
+    console.error('Error running TypeScript', error);
     process.exit(1);
   });
 }

utils/fetch_devices.js

@@ -80,8 +80,8 @@ async function main(url) {
   let json = null;
   try {
     json = JSON.parse(text);
-  } catch (e) {
+  } catch (error) {
-    console.error(`FAILED: error parsing response - ${e.message}`);
+    console.error(`FAILED: error parsing response - ${error.message}`);
     return;
   }
   const devicePayloads = json.extensions.filter(extension => extension.type === 'emulated-device').map(extension => extension.device);