Enable ESLint no-unused-expressions rule (#4363)

# Description of Changes
Enable ESLint [no-unused-expressions
rule](https://typescript-eslint.io/rules/no-unused-expressions/)

.editorconfig

@@ -24,7 +24,7 @@ indent_size = 2
 insert_final_newline = false
 trim_trailing_whitespace = false
 
-[{*.js,*.jsx,*.ts,*.tsx}]
+[{*.js,*.jsx,*.mjs,*.ts,*.tsx}]
 indent_size = 2
 
 [*.css]

.github/workflows/build.yml

@@ -147,6 +147,8 @@ jobs:
           cache-dependency-path: frontend/package-lock.json
       - name: Install frontend dependencies
         run: cd frontend && npm ci
+      - name: Lint frontend
+        run: cd frontend && npm run lint
       - name: Build frontend
         run: cd frontend && npm run build
       - name: Run frontend tests

.vscode/extensions.json

@@ -19,5 +19,6 @@
     "yzhang.markdown-all-in-one", // Markdown All-in-One extension for enhanced Markdown editing
     "stylelint.vscode-stylelint", // Stylelint extension for CSS and SCSS linting
     "redhat.vscode-yaml", // YAML extension for Visual Studio Code
+    "dbaeumer.vscode-eslint", // ESLint extension for TypeScript linting
   ]
 }

frontend/eslint.config.mjs

@@ -0,0 +1,28 @@
+// @ts-check
+
+import eslint from '@eslint/js';
+import { defineConfig } from 'eslint/config';
+import tseslint from 'typescript-eslint';
+
+export default defineConfig(
+  eslint.configs.recommended,
+  tseslint.configs.recommended,
+  {
+    ignores: [
+      "dist", // Contains 3rd party code
+      "public", // Contains 3rd party code
+    ],
+  },
+  {
+    rules: {
+      "no-empty-pattern": "off", // Temporarily disabled until codebase conformant
+      "no-undef": "off", // Temporarily disabled until codebase conformant
+      "no-case-declarations": "off", // Temporarily disabled until codebase conformant
+      "@typescript-eslint/ban-ts-comment": "off", // Temporarily disabled until codebase conformant
+      "@typescript-eslint/no-empty-object-type": "off", // Temporarily disabled until codebase conformant
+      "@typescript-eslint/no-explicit-any": "off", // Temporarily disabled until codebase conformant
+      "@typescript-eslint/no-require-imports": "off", // Temporarily disabled until codebase conformant
+      "@typescript-eslint/no-unused-vars": "off", // Temporarily disabled until codebase conformant
+    },
+  }
+);

frontend/package.json

@@ -40,6 +40,7 @@
     "predev": "npm run generate-icons",
     "dev": "npx tsc --noEmit && vite",
     "prebuild": "npm run generate-icons",
+    "lint": "npx eslint",
     "build": "npx tsc --noEmit && vite build",
     "preview": "vite preview",
     "typecheck": "tsc --noEmit",
@@ -72,6 +73,7 @@
     ]
   },
   "devDependencies": {
+    "@eslint/js": "^9.34.0",
     "@iconify-json/material-symbols": "^1.2.33",
     "@iconify/utils": "^3.0.1",
     "@playwright/test": "^1.40.0",
@@ -80,6 +82,7 @@
     "@types/react-dom": "^19.1.5",
     "@vitejs/plugin-react": "^4.5.0",
     "@vitest/coverage-v8": "^1.0.0",
+    "eslint": "^9.34.0",
     "jsdom": "^23.0.0",
     "license-checker": "^25.0.1",
     "madge": "^8.0.0",
@@ -87,7 +90,8 @@
     "postcss-cli": "^11.0.1",
     "postcss-preset-mantine": "^1.17.0",
     "postcss-simple-vars": "^7.0.1",
-    "typescript": "^5.8.3",
+    "typescript": "^5.9.2",
+    "typescript-eslint": "^8.42.0",
     "vite": "^6.3.5",
     "vitest": "^1.0.0"
   }

frontend/scripts/generate-licenses.js

@@ -224,7 +224,7 @@ function getLicenseUrl(licenseType) {
     // Handle complex SPDX expressions like "(MIT AND Zlib)" or "(MIT OR CC0-1.0)"
     if (licenseType.includes('AND') || licenseType.includes('OR')) {
         // Extract the first license from compound expressions for URL
-        const match = licenseType.match(/\(?\s*([A-Za-z0-9\-\.]+)/);
+        const match = licenseType.match(/\(?\s*([A-Za-z0-9\-.]+)/);
         if (match && licenseUrls[match[1]]) {
             return licenseUrls[match[1]];
         }

frontend/src/components/shared/fitText/textFit.ts

@@ -82,8 +82,8 @@ export function adjustFontSizeToFit(
 
   return () => {
     cancelAnimationFrame(raf);
-    try { ro.disconnect(); } catch {}
+    try { ro.disconnect(); } catch { /* Ignore errors */ }
-    try { mo.disconnect(); } catch {}
+    try { mo.disconnect(); } catch { /* Ignore errors */ }
   };
 }
 

frontend/src/components/tools/toolPicker/ToolSearch.tsx

@@ -126,7 +126,7 @@ const ToolSearch = ({
                 key={id}
                 variant="subtle"
                 onClick={() => {
-                  onToolSelect && onToolSelect(id);
+                  onToolSelect?.(id);
                   setDropdownOpen(false);
                 }}
                 leftSection={<div style={{ color: "var(--tools-text-and-icon-color)" }}>{tool.icon}</div>}

frontend/src/index.tsx

@@ -35,8 +35,11 @@ function updatePosthogConsent(){
       return;
     }
     const optIn = (window.CookieConsent as any).acceptedCategory('analytics');
-    optIn?
+    if (optIn) {
-      posthog.opt_in_capturing() : posthog.opt_out_capturing();
+      posthog.opt_in_capturing();
+    } else {
+      posthog.opt_out_capturing();
+    }
 
     console.log("Updated analytics consent: ", optIn? "opted in" : "opted out");
   }

frontend/src/services/enhancedPDFProcessingService.ts

@@ -182,7 +182,7 @@ export class EnhancedPDFProcessingService {
   ): Promise<ProcessedFile> {
     const arrayBuffer = await file.arrayBuffer();
     const pdf = await pdfWorkerManager.createDocument(arrayBuffer);
-    
+
     try {
       const totalPages = pdf.numPages;
 
@@ -519,10 +519,7 @@ export class EnhancedPDFProcessingService {
     this.notifyListeners();
 
     // Force memory cleanup hint
-    if (typeof window !== 'undefined' && window.gc) {
+    setTimeout(() => window.gc?.(), 100);
-      let gc = window.gc;
-      setTimeout(() => gc(), 100);
-    }
   }
 
   /**

frontend/src/services/indexedDBManager.ts

@@ -73,7 +73,7 @@ class IndexedDBManager {
       request.onsuccess = () => {
         const db = request.result;
         console.log(`Successfully opened ${config.name}`);
-        
+
         // Set up close handler to clean up our references
         db.onclose = () => {
           console.log(`Database ${config.name} closed`);
@@ -87,13 +87,11 @@ class IndexedDBManager {
       request.onupgradeneeded = (event) => {
         const db = request.result;
         const oldVersion = event.oldVersion;
-        
+
         console.log(`Upgrading ${config.name} from v${oldVersion} to v${config.version}`);
 
         // Create or update object stores
         config.stores.forEach(storeConfig => {
-          let store: IDBObjectStore;
-
           if (db.objectStoreNames.contains(storeConfig.name)) {
             // Store exists - for now, just continue (could add migration logic here)
             console.log(`Object store '${storeConfig.name}' already exists`);
@@ -109,7 +107,7 @@ class IndexedDBManager {
             options.autoIncrement = storeConfig.autoIncrement;
           }
 
-          store = db.createObjectStore(storeConfig.name, options);
+          const store = db.createObjectStore(storeConfig.name, options);
           console.log(`Created object store '${storeConfig.name}'`);
 
           // Create indexes
@@ -168,7 +166,7 @@ class IndexedDBManager {
 
     return new Promise((resolve, reject) => {
       const deleteRequest = indexedDB.deleteDatabase(name);
-      
+
       deleteRequest.onerror = () => reject(deleteRequest.error);
       deleteRequest.onsuccess = () => {
         console.log(`Deleted database: ${name}`);
@@ -224,4 +222,4 @@ export const DATABASE_CONFIGS = {
   } as DatabaseConfig
 } as const;
 
-export const indexedDBManager = IndexedDBManager.getInstance();
+export const indexedDBManager = IndexedDBManager.getInstance();

frontend/src/services/pdfExportService.ts

@@ -130,7 +130,7 @@ export class PDFExportService {
     newDoc.setModificationDate(new Date());
 
     const pdfBytes = await newDoc.save();
-    return new Blob([pdfBytes], { type: 'application/pdf' });
+    return new Blob([pdfBytes as BlobPart], { type: 'application/pdf' });
   }
 
   /**
@@ -176,7 +176,7 @@ export class PDFExportService {
     newDoc.setModificationDate(new Date());
 
     const pdfBytes = await newDoc.save();
-    return new Blob([pdfBytes], { type: 'application/pdf' });
+    return new Blob([pdfBytes as BlobPart], { type: 'application/pdf' });
   }
 
 

frontend/src/services/pdfWorkerManager.ts

@@ -1,6 +1,6 @@
 /**
  * PDF.js Worker Manager - Centralized worker lifecycle management
- * 
+ *
  * Prevents infinite worker creation by managing PDF.js workers globally
  * and ensuring proper cleanup when operations complete.
  */
@@ -86,7 +86,7 @@ class PDFWorkerManager {
       const pdf = await loadingTask.promise;
       this.activeDocuments.add(pdf);
       this.workerCount++;
-      
+
       return pdf;
     } catch (error) {
       // If document creation fails, make sure to clean up the loading task
@@ -94,6 +94,7 @@ class PDFWorkerManager {
         try {
           loadingTask.destroy();
         } catch (destroyError) {
+          // Ignore errors
         }
       }
       throw error;
@@ -125,7 +126,7 @@ class PDFWorkerManager {
     documentsToDestroy.forEach(pdf => {
       this.destroyDocument(pdf);
     });
-    
+
     this.activeDocuments.clear();
     this.workerCount = 0;
   }
@@ -166,9 +167,10 @@ class PDFWorkerManager {
       try {
         pdf.destroy();
       } catch (error) {
+        // Ignore errors
       }
     });
-    
+
     this.activeDocuments.clear();
     this.workerCount = 0;
   }
@@ -182,4 +184,4 @@ class PDFWorkerManager {
 }
 
 // Export singleton instance
-export const pdfWorkerManager = PDFWorkerManager.getInstance();
+export const pdfWorkerManager = PDFWorkerManager.getInstance();