chore(ts): enable noFallthroughCasesInSwitch and noImplicitOverride (#577)

Turn on both compiler checks in the root TypeScript configuration, which
apps/web, apps/api, apps/extension, packages/shared and packages/plugin-api
extend, and in the separate Expo configuration of apps/mobile.

No switch statement falls through today. The 19 members that override a
base class member (React error boundaries, the local database recovery
error and the vendored poster badge) now declare `override`; this only
changes type checking and is erased from the emitted JavaScript.

apps/mobile/tsconfig.json

@@ -3,6 +3,8 @@
   "compilerOptions": {
     "ignoreDeprecations": "6.0",
     "strict": true,
+    "noFallthroughCasesInSwitch": true,
+    "noImplicitOverride": true,
     "baseUrl": ".",
     "paths": {
       "@/*": [

apps/web/src/components/DesktopRendererErrorBoundary.tsx

@@ -17,7 +17,7 @@ type State = {
 const isChineseInterface = () => navigator.language.toLowerCase().startsWith("zh");
 
 export class DesktopRendererErrorBoundary extends React.Component<{ children: ReactNode }, State> {
-  state: State = { error: null, reporting: false };
+  override state: State = { error: null, reporting: false };
 
   static getDerivedStateFromError(error: unknown): Pick<State, "error"> {
     const normalized = error instanceof Error ? error : new Error(String(error));
@@ -31,7 +31,7 @@ export class DesktopRendererErrorBoundary extends React.Component<{ children: Re
     };
   }
 
-  componentDidCatch(error: Error, info: ErrorInfo) {
+  override componentDidCatch(error: Error, info: ErrorInfo) {
     markRendererRecoveryRequired();
     const details: RendererErrorDetails = {
       kind: "react-error",
@@ -56,7 +56,7 @@ export class DesktopRendererErrorBoundary extends React.Component<{ children: Re
     }
   };
 
-  render() {
+  override render() {
     if (!this.state.error) return this.props.children;
     const zh = isChineseInterface();
     const desktop = Boolean(window.edgeeverDesktop?.isAvailable);

apps/web/src/components/EditorPaneErrorBoundary.tsx

@@ -14,13 +14,13 @@ type State = {
 const isChineseInterface = () => navigator.language.toLowerCase().startsWith("zh");
 
 export class EditorPaneErrorBoundary extends React.Component<Props, State> {
-  state: State = { error: null };
+  override state: State = { error: null };
 
   static getDerivedStateFromError(error: unknown): State {
     return { error: error instanceof Error ? error : new Error(String(error)) };
   }
 
-  componentDidCatch(error: Error, info: ErrorInfo) {
+  override componentDidCatch(error: Error, info: ErrorInfo) {
     markRendererRecoveryRequired();
     const details = {
       kind: "react-error" as const,
@@ -32,7 +32,7 @@ export class EditorPaneErrorBoundary extends React.Component<Props, State> {
     void window.edgeeverDesktop?.recordRendererError(details).catch(() => undefined);
   }
 
-  componentDidUpdate(previousProps: Props) {
+  override componentDidUpdate(previousProps: Props) {
     if (this.state.error && previousProps.resetKey !== this.props.resetKey) {
       clearRendererRecoveryRequired();
       this.setState({ error: null });
@@ -44,7 +44,7 @@ export class EditorPaneErrorBoundary extends React.Component<Props, State> {
     this.setState({ error: null });
   };
 
-  render() {
+  override render() {
     if (!this.state.error) return this.props.children;
     const zh = isChineseInterface();
 

apps/web/src/components/ai-sidebar/AiSidebarErrorBoundary.tsx

@@ -9,17 +9,17 @@ type Props = {
 type State = { failed: boolean };
 
 export class AiSidebarErrorBoundary extends React.Component<Props, State> {
-  state: State = { failed: false };
+  override state: State = { failed: false };
 
   static getDerivedStateFromError(): State {
     return { failed: true };
   }
 
-  componentDidCatch(error: Error, info: ErrorInfo) {
+  override componentDidCatch(error: Error, info: ErrorInfo) {
     console.error("Caught AI sidebar error", error, info.componentStack);
   }
 
-  render() {
+  override render() {
     if (!this.state.failed) return this.props.children;
     if (!this.props.open) return null;
     const zh = navigator.language.toLowerCase().startsWith("zh");

apps/web/src/lib/local-database-recovery.ts

@@ -9,7 +9,7 @@ class LocalDatabaseOperationTimeoutError extends Error {
 }
 
 export class LocalDatabaseUnavailableError extends Error {
-  readonly cause: unknown;
+  override readonly cause: unknown;
 
   constructor(cause: unknown) {
     super("Browser local storage is not responding");

apps/web/src/lib/poster-design/vendor/qiaomu/badge.ts

@@ -21,20 +21,20 @@ export function measureLabel(text: string, size: number, weight: string, family:
 }
 
 export class BadgeBox extends Textbox {
-  static type = 'BadgeBox';
-  static customProperties = ['badgeBg', 'padX', 'padY', 'radius'];
+  static override type = 'BadgeBox';
+  static override customProperties = ['badgeBg', 'padX', 'padY', 'radius'];
   declare badgeBg: string; declare padX: number; declare padY: number; declare radius: number;
   constructor(text: string, options?: Partial<TextboxProps> & Partial<BadgeProps>) { super(text, { badgeBg: '#111111', padX: 0.6, padY: 0.34, radius: 0.5, editable: false, lineHeight: 1, ...options } as Partial<TextboxProps>); }
   private metrics(): Metrics { return measureLabel(this.text.trim(), this.fontSize, String(this.fontWeight), this.fontFamily); }
   /** Size comes from the measured label, not from Fabric's line layout. */
-  initDimensions(): void {
+  override initDimensions(): void {
     const m = this.metrics(); const px = this.padX * this.fontSize, py = this.padY * this.fontSize;
     this.width = m.width + px * 2; this.height = m.ascent + m.descent + py * 2;
     this.textLines = [this.text]; this._textLines = [[...this.text]]; this.dirty = true;
   }
   /** The pill is the visible extent. Fabric's own line cache is never filled here, so its version would throw. */
-  getLineWidth(): number { return this.width; }
-  _render(c: CanvasRenderingContext2D): void {
+  override getLineWidth(): number { return this.width; }
+  override _render(c: CanvasRenderingContext2D): void {
     const w = this.width, h = this.height; const m = this.metrics(); const r = Math.min(h / 2, this.radius * h);
     c.save(); c.fillStyle = this.badgeBg; c.beginPath();
     c.moveTo(-w / 2 + r, -h / 2); c.arcTo(w / 2, -h / 2, w / 2, h / 2, r); c.arcTo(w / 2, h / 2, -w / 2, h / 2, r); c.arcTo(-w / 2, h / 2, -w / 2, -h / 2, r); c.arcTo(-w / 2, -h / 2, w / 2, -h / 2, r); c.closePath(); c.fill();

apps/web/src/mobile-edit.tsx

@@ -38,17 +38,17 @@ const returnToPreviousPage = () => {
 };
 
 class MobileEditorErrorBoundary extends React.Component<React.PropsWithChildren, MobileEditorErrorBoundaryState> {
-  state: MobileEditorErrorBoundaryState = { failed: false };
+  override state: MobileEditorErrorBoundaryState = { failed: false };
 
   static getDerivedStateFromError(): MobileEditorErrorBoundaryState {
     return { failed: true };
   }
 
-  componentDidCatch(error: Error) {
+  override componentDidCatch(error: Error) {
     console.error("Mobile editor crashed", error);
   }
 
-  render() {
+  override render() {
     if (!this.state.failed) return this.props.children;
     const english = (getBrowserLocale() ?? defaultLocale) === "en-US";
     return (

tsconfig.json

@@ -9,6 +9,8 @@
     "isolatedModules": true,
     "jsx": "react-jsx",
     "strict": true,
+    "noFallthroughCasesInSwitch": true,
+    "noImplicitOverride": true,
     "noEmit": true,
     "skipLibCheck": true,
     "ignoreDeprecations": "6.0",