chore(null): null strictness fixes for 9/15's top 10 null:find results (

#3359)

#### Description of changes

Another round of the top ten `yarn null:find` results, plus the extra dependent files that `yarn null:autoadd` revealed were fixed as a side effect of the first fixes.

The most interesting/notable change here is in the error handling improvements to `target-tab-finder.ts`; previously, a few edge cases the browser could return to us would result in a string error or a "cannot reference property url of undefined" error, where now they will throw more meaningful `Error` objects. Tests were updated to accomodate.

Before:
```sh
> yarn null:progress

**43%** complete (**573**/1343 non-test files)
```

After:
```sh
> yarn null:progress

**45%** complete (**599**/1343 non-test files)
```

#### Pull request checklist
<!-- If a checklist item is not applicable to this change, write "n/a" in the checkbox -->
- [x] Addresses an existing issue: #2869
- [x] Ran `yarn fastpass`
- [x] Added/updated relevant unit test(s) (and ran `yarn test`)
- [x] Verified code coverage for the changes made. Check coverage report at: `<rootDir>/test-results/unit/coverage`
- [x] PR title *AND* final merge commit title both start with a semantic tag (`fix:`, `chore:`, `feat(feature-name):`, `refactor:`). See `CONTRIBUTING.md`.
- [n/a] (UI changes only) Added screenshots/GIFs to description above
- [n/a] (UI changes only) Verified usability with NVDA/JAWS

src/common/components/header.tsx

@@ -16,7 +16,7 @@ export type HeaderProps = {
     navMenu?: JSX.Element;
     showHeaderTitle?: boolean;
     showFarItems?: boolean;
-    narrowModeStatus?: NarrowModeStatus;
+    narrowModeStatus: NarrowModeStatus;
 };
 
 export const Header = NamedFC<HeaderProps>('Header', props => {

src/common/url-validator.ts

@@ -5,7 +5,10 @@ import { BrowserAdapter } from './browser-adapters/browser-adapter';
 export class UrlValidator {
     constructor(private readonly browserAdapter: BrowserAdapter) {}
 
-    public async isSupportedUrl(url: string): Promise<boolean> {
+    public async isSupportedUrl(url?: string): Promise<boolean> {
+        if (url == null) {
+            return false;
+        }
         const lowerCasedUrl: string = url.toLowerCase();
         if (lowerCasedUrl.startsWith('http://') || lowerCasedUrl.startsWith('https://')) {
             return this.hasSupportedPrefix(lowerCasedUrl);

src/electron/flux/action-creator/android-setup-action-creator.ts

@@ -13,5 +13,5 @@ export class AndroidSetupActionCreator {
     public saveAdbPath = (newAdbPath: string) => this.setupActions.saveAdbPath.invoke(newAdbPath);
     public setSelectedDevice = (device: DeviceInfo) =>
         this.setupActions.setSelectedDevice.invoke(device);
-    public readyToStart = () => this.setupActions.readyToStart.invoke(null, this.scope);
+    public readyToStart = () => this.setupActions.readyToStart.invoke(undefined, this.scope);
 }

src/electron/ipc/ipc-renderer-shim.ts

@@ -45,15 +45,15 @@ export class IpcRendererShim {
     }
 
     private onMaximize = (): void => {
-        this.fromBrowserWindowMaximize.invoke(null, this.invokeScope);
+        this.fromBrowserWindowMaximize.invoke(undefined, this.invokeScope);
     };
 
     private onEnterFullScreen = (): void => {
-        this.fromBrowserWindowEnterFullScreen.invoke(null, this.invokeScope);
+        this.fromBrowserWindowEnterFullScreen.invoke(undefined, this.invokeScope);
     };
 
     private onUnmaximize = (): void => {
-        this.fromBrowserWindowUnmaximize.invoke(null, this.invokeScope);
+        this.fromBrowserWindowUnmaximize.invoke(undefined, this.invokeScope);
     };
 
     private onClose = async (): Promise<void> => {

src/popup/target-tab-finder.ts

@@ -29,7 +29,12 @@ export class TargetTabFinder {
         if (tabIdInUrl == null) {
             return this.browserAdapter
                 .tabsQuery({ active: true, currentWindow: true })
-                .then(tabs => tabs.pop());
+                .then(tabs => {
+                    if (tabs.length === 0) {
+                        throw new Error('No active tabs found for current window');
+                    }
+                    return tabs.pop()!;
+                });
         } else {
             return new Promise((resolve, reject) => {
                 this.browserAdapter.getTab(
@@ -38,7 +43,7 @@ export class TargetTabFinder {
                         resolve(tab);
                     },
                     () => {
-                        reject(`Tab with Id ${tabIdInUrl} not found`);
+                        reject(new Error(`Tab with Id ${tabIdInUrl} not found`));
                     },
                 );
             });

src/reports/components/new-tab-link-confirmation-dialog.tsx

@@ -40,7 +40,7 @@ const addConfirmOnClickHandler = function (
     doc: Document,
     confirmCallback: ConfirmType,
 ): void {
-    const targetPageLink = doc.getElementById(linkId);
+    const targetPageLink = doc.getElementById(linkId)!;
     targetPageLink.addEventListener('click', function (event): void {
         const result = confirmCallback(
             'Are you sure you want to navigate away from the Accessibility Insights report?\n' +

src/scanner/custom-rules/native-widgets-default.ts

@@ -51,7 +51,7 @@ export function evaluateNativeWidget(node: HTMLElement): boolean {
     return true;
 }
 
-export function getNativeWidgetElementType(node: HTMLElement): string {
+export function getNativeWidgetElementType(node: HTMLElement): string | undefined {
     if (node.tagName === 'BUTTON' || node.tagName === 'SELECT' || node.tagName === 'TEXTAREA') {
         return node.tagName.toLowerCase();
     } else if (node.tagName === 'INPUT' && node.hasAttribute('list')) {

src/tests/unit/tests/common/components/header.test.tsx

@@ -7,14 +7,18 @@ import { Header, HeaderDeps } from 'common/components/header';
 import { NarrowModeStatus } from 'DetailsView/components/narrow-mode-detector';
 
 describe('Header', () => {
+    const stubNarrowModeStatus = {
+        isHeaderAndNavCollapsed: false,
+    } as NarrowModeStatus;
+
     it('renders per snapshot', () => {
         const applicationTitle = 'THE_APPLICATION_TITLE';
         const deps = {
             textContent: {
                 applicationTitle,
             },
         } as HeaderDeps;
-        const wrapper = shallow(<Header deps={deps} />);
+        const wrapper = shallow(<Header deps={deps} narrowModeStatus={stubNarrowModeStatus} />);
         expect(wrapper.getElement()).toMatchSnapshot();
     });
 
@@ -25,7 +29,9 @@ describe('Header', () => {
                 applicationTitle,
             },
         } as HeaderDeps;
-        const wrapper = shallow(<Header deps={deps} showHeaderTitle={false} />);
+        const wrapper = shallow(
+            <Header deps={deps} showHeaderTitle={false} narrowModeStatus={stubNarrowModeStatus} />,
+        );
         expect(wrapper.getElement()).toMatchSnapshot();
     });
 
@@ -41,6 +47,7 @@ describe('Header', () => {
                 deps={deps}
                 farItems={<div>THis is far items!</div>}
                 showFarItems={showFarItems}
+                narrowModeStatus={stubNarrowModeStatus}
             />,
         );
         expect(wrapper.getElement()).toMatchSnapshot();

src/tests/unit/tests/common/url-validator.test.ts

@@ -20,6 +20,8 @@ describe('UrlValidatorTest', () => {
         ['http://domain-with-no-trailing-slash', true],
         ['http:/oops', false],
         ['oops_http://example.com', false],
+        [null, false],
+        [undefined, false],
     ];
 
     beforeEach(() => {

src/tests/unit/tests/electron/flux/action-creator/android-setup-action-creator.test.ts

@@ -72,7 +72,7 @@ describe(AndroidSetupActionCreator, () => {
     });
 
     it('invokes readyToStart action on readyToStart', () => {
-        const readyToStartMock = createActionMock<void>(null, 'AndroidSetupActionCreator');
+        const readyToStartMock = createActionMock<void>(undefined, 'AndroidSetupActionCreator');
         androidSetupActionsMock
             .setup(actions => actions.readyToStart)
             .returns(() => readyToStartMock.object);

src/tests/unit/tests/popup/target-tab-finder.test.ts

@@ -15,7 +15,7 @@ describe('TargetTabFinderTest', () => {
     let urlParserMock: IMock<UrlParser>;
     let urlValidatorMock: IMock<UrlValidator>;
     const tabId: number = 15;
-    let tabStub: Tab;
+    let tabStub: Tabs.Tab;
 
     beforeEach(() => {
         windowStub = {
@@ -28,7 +28,7 @@ describe('TargetTabFinderTest', () => {
             id: tabId,
             title: 'some title',
             url: 'target page url',
-        };
+        } as Tabs.Tab;
 
         browserAdapterMock = Mock.ofType<BrowserAdapter>();
         urlParserMock = Mock.ofType(UrlParser);
@@ -72,7 +72,7 @@ describe('TargetTabFinderTest', () => {
             setupGetTabCall();
         } else {
             setupGetTabIdParamFromUrl(null);
-            setupTabQueryCall();
+            setupTabQueryCall([tabStub]);
         }
 
         setupIsSupportedCall(testCase.isUrlSupported);
@@ -84,17 +84,25 @@ describe('TargetTabFinderTest', () => {
         });
     });
 
-    test('no tab found', async () => {
+    it('throws an error if tabId URL parameter is not found', async () => {
         setupGetTabIdParamFromUrl(tabId);
         browserAdapterMock
             .setup(b => b.getTab(tabId, It.isAny(), It.isAny()))
             .callback((id, cb, reject) => {
                 reject();
             });
-        setupIsSupportedCall(true);
-        await testSubject
-            .getTargetTab()
-            .catch(error => expect(error).toEqual(`Tab with Id ${tabId} not found`));
+
+        await expect(testSubject.getTargetTab()).rejects.toThrowError(
+            `Tab with Id ${tabId} not found`,
+        );
+    });
+
+    it('throws an error there is neither a tabId URL parameter nor an active tab', async () => {
+        setupTabQueryCall([]);
+
+        await expect(testSubject.getTargetTab()).rejects.toThrowError(
+            'No active tabs found for current window',
+        );
     });
 
     function setupGetTabIdParamFromUrl(tabIdValue: number | null): void {
@@ -111,10 +119,10 @@ describe('TargetTabFinderTest', () => {
             });
     }
 
-    function setupTabQueryCall(): void {
+    function setupTabQueryCall(returnValue: Tabs.Tab[]): void {
         browserAdapterMock
             .setup(adapter => adapter.tabsQuery({ active: true, currentWindow: true }))
-            .returns(() => Promise.resolve([tabStub as Tabs.Tab]));
+            .returns(() => Promise.resolve(returnValue));
     }
 
     function setupIsSupportedCall(isSupported: boolean): void {

tsconfig.strictNullChecks.json

@@ -21,6 +21,7 @@
         "./src/DetailsView/components/left-nav/test-view-left-nav-link.tsx",
         "./src/DetailsView/components/narrow-mode-detector.tsx",
         "./src/DetailsView/components/nav-link-button.tsx",
+        "./src/DetailsView/components/no-content-available/no-content-available-view.tsx",
         "./src/DetailsView/components/no-content-available/no-content-available.tsx",
         "./src/DetailsView/components/no-displayable-preview-features-message.tsx",
         "./src/DetailsView/components/overview-content/overview-heading.tsx",
@@ -189,6 +190,7 @@
         "./src/debug-tools/components/telemetry-viewer/telemetry-viewer.tsx",
         "./src/electron/common/electron-telemetry-events.ts",
         "./src/electron/common/get-electron-icon-path.ts",
+        "./src/electron/flux/action-creator/android-setup-action-creator.ts",
         "./src/electron/flux/action-creator/scan-action-creator.ts",
         "./src/electron/flux/action-creator/window-frame-action-creator.ts",
         "./src/electron/flux/store/scan-store.ts",
@@ -198,10 +200,6 @@
         "./src/electron/flux/types/scan-store-data.ts",
         "./src/electron/flux/types/window-state-store-data.ts",
         "./src/electron/flux/types/window-state.ts",
-        "./src/electron/ipc/async-action.ts",
-        "./src/electron/ipc/ipc-channel-names.ts",
-        "./src/electron/ipc/ipc-message-dispatcher.ts",
-        "./src/electron/ipc/ipc-message-receiver.ts",
         "./src/electron/main/main-window-config.ts",
         "./src/electron/main/main-window-renderer-message-handlers.ts",
         "./src/electron/platform/android/adb-wrapper.ts",
@@ -210,10 +208,13 @@
         "./src/electron/platform/android/appium-adb-wrapper.ts",
         "./src/electron/platform/android/device-config.ts",
         "./src/electron/platform/android/live-appium-adb-creator.ts",
+        "./src/electron/platform/android/setup/android-port-cleaner.ts",
         "./src/electron/platform/android/setup/android-service-configurator-factory.ts",
         "./src/electron/platform/android/setup/android-service-configurator.ts",
         "./src/electron/platform/android/setup/android-setup-deps.ts",
         "./src/electron/platform/android/setup/android-setup-step-id.ts",
+        "./src/electron/platform/android/setup/port-cleaning-service-configurator-factory.ts",
+        "./src/electron/platform/android/setup/port-cleaning-service-configurator.ts",
         "./src/electron/platform/android/setup/state-machine/state-machine-action-callback.ts",
         "./src/electron/platform/android/setup/state-machine/state-machine-step-configs.ts",
         "./src/electron/platform/android/setup/state-machine/state-machine-step.ts",
@@ -224,10 +225,21 @@
         "./src/electron/views/automated-checks/components/title-bar.tsx",
         "./src/electron/views/bundled-renderer-styles.ts",
         "./src/electron/views/common/window-title/window-title.tsx",
+        "./src/electron/views/device-connect-view/components/android-setup/android-setup-spinner-step.tsx",
         "./src/electron/views/device-connect-view/components/android-setup/android-setup-spinner.tsx",
+        "./src/electron/views/device-connect-view/components/android-setup/android-setup-step-container.tsx",
         "./src/electron/views/device-connect-view/components/android-setup/android-setup-step-layout.tsx",
+        "./src/electron/views/device-connect-view/components/android-setup/android-setup-types.ts",
+        "./src/electron/views/device-connect-view/components/android-setup/configuring-port-forwarding-step.tsx",
+        "./src/electron/views/device-connect-view/components/android-setup/detect-adb-step.tsx",
+        "./src/electron/views/device-connect-view/components/android-setup/detect-devices-step.tsx",
+        "./src/electron/views/device-connect-view/components/android-setup/detect-permissions-step.tsx",
+        "./src/electron/views/device-connect-view/components/android-setup/detect-service-step.tsx",
         "./src/electron/views/device-connect-view/components/android-setup/device-description.tsx",
         "./src/electron/views/device-connect-view/components/android-setup/folder-picker.tsx",
+        "./src/electron/views/device-connect-view/components/android-setup/installing-service-step.tsx",
+        "./src/electron/views/device-connect-view/components/android-setup/prompt-locate-adb-step.tsx",
+        "./src/electron/views/device-connect-view/components/android-setup/wait-to-start-step.tsx",
         "./src/electron/views/device-connect-view/components/automation-ids.ts",
         "./src/electron/views/device-connect-view/components/electron-external-link.tsx",
         "./src/electron/views/device-connect-view/components/electron-link.tsx",
@@ -239,6 +251,7 @@
         "./src/electron/views/root-container/components/platform-body-class-modifier.tsx",
         "./src/electron/views/screenshot/screenshot.tsx",
         "./src/electron/window-management/platform-info.ts",
+        "./src/electron/window-management/window-frame-updater.ts",
         "./src/injected/adapters/resolution-creator.ts",
         "./src/injected/analyzers/filter-results.ts",
         "./src/injected/client-utils.ts",
@@ -269,6 +282,7 @@
         "./src/popup/components/header.tsx",
         "./src/popup/components/launch-pad-item-row.tsx",
         "./src/popup/incompatible-browser-renderer.tsx",
+        "./src/popup/target-tab-finder.ts",
         "./src/reports/assessment-report.styles.ts",
         "./src/reports/automated-checks-report.styles.ts",
         "./src/reports/components/assessment-report-body-header.tsx",
@@ -277,6 +291,7 @@
         "./src/reports/components/header-bar.tsx",
         "./src/reports/components/inline-image.tsx",
         "./src/reports/components/instance-outcome-type.ts",
+        "./src/reports/components/new-tab-link-confirmation-dialog.tsx",
         "./src/reports/components/report-head.tsx",
         "./src/reports/components/report-sections/body-section.tsx",
         "./src/reports/components/report-sections/collapsible-script-provider.tsx",
@@ -285,6 +300,7 @@
         "./src/reports/components/report-sections/no-failed-instances-congrats.tsx",
         "./src/reports/components/report-sections/report-footer.tsx",
         "./src/reports/components/report-sections/summary-report-header-section.tsx",
+        "./src/reports/components/report-sections/summary-results-table.tsx",
         "./src/reports/components/report-sections/title-section.tsx",
         "./src/reports/components/report-sections/tool-link.tsx",
         "./src/reports/components/summary-report-head.tsx",
@@ -307,9 +323,11 @@
         "./src/scanner/custom-rules/header-rule.ts",
         "./src/scanner/custom-rules/heading-rule.ts",
         "./src/scanner/custom-rules/link-purpose.ts",
+        "./src/scanner/custom-rules/native-widgets-default.ts",
         "./src/scanner/custom-rules/page-title.ts",
         "./src/scanner/custom-rules/text-contrast.ts",
         "./src/scanner/custom-rules/unique-landmark.ts",
+        "./src/scanner/custom-rules/widget-function.ts",
         "./src/scanner/document-utils.ts",
         "./src/scanner/help-url-getter.ts",
         "./src/scanner/iruleresults.d.ts",
@@ -338,6 +356,7 @@
         "./src/tests/end-to-end/common/playwright-option-types.ts",
         "./src/tests/end-to-end/common/prepare-test-result-file-path.ts",
         "./src/tests/end-to-end/common/pretty-print-axe-violations.ts",
+        "./src/tests/end-to-end/common/scan-for-accessibility-issues.ts",
         "./src/tests/end-to-end/common/screenshot-on-error.ts",
         "./src/tests/end-to-end/common/test-resources.ts",
         "./src/tests/end-to-end/common/timeouts.ts",
@@ -365,7 +384,9 @@
         "./src/tests/unit/tests/injected/visualization/drawer-utils-mock-builder.ts",
         "./src/tests/unit/tests/scanner/custom-rules-configuration-stub.ts",
         "./src/tests/unit/tests/scanner/mock-axe-utils.ts",
-        "./src/views/content/guidance-title.tsx"
+        "./src/views/content/content-view.tsx",
+        "./src/views/content/guidance-title.tsx",
+        "./src/views/page/page.tsx"
     ],
     "include": [
         "src/Devtools/**/*",
@@ -392,6 +413,7 @@
         "src/electron/auto-update/**/*",
         "src/electron/electron-builder/**/*",
         "src/electron/flux/action/**/*",
+        "src/electron/ipc/**/*",
         "src/electron/resources/**/*",
         "src/icons/**/*",
         "src/issue-filing/common/markup/**/*",