🧹 chore: Migrate to Flat ESLint Config & Update Prettier Settings (#5737)

* chore: migrated eslint v8 to v9

* chore: migrated eslint v8 to v9

* ESLint only checks the files that have changed in the pull request.

* fix: ESLint only checks the files that have changed in the pull request.

* refactor: eslint only on changed files

* refactor: eslint only on changed files or added files

* refactor: eslint only on changed files or added files

* refactor: eslint only on changed files or added files

but only include files that are not deleted (ACMRTUXB: A, C, M, R, T, U, X, B).

* whoops missed something

.github/workflows/backend-review.yml

@@ -38,7 +38,7 @@ jobs:
 
       - name: Install MCP Package
         run: npm run build:mcp
-      
+
       - name: Create empty auth.json file
         run: |
           mkdir -p api/data
@@ -61,9 +61,4 @@ jobs:
         run: cd api && npm run test:ci
 
       - name: Run librechat-data-provider unit tests
-        run: cd packages/data-provider && npm run test:ci
-
-      - name: Run linters
-        uses: wearerequired/lint-action@v2
-        with:
-          eslint: true
+        run: cd packages/data-provider && npm run test:ci

.github/workflows/eslint-ci.yml

@@ -0,0 +1,96 @@
+name: ESLint Code Quality Checks
+on:
+  pull_request:
+    branches:
+      - main
+      - dev
+      - release/*
+
+jobs:
+  eslint_checks:
+    name: Run ESLint Linting
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      security-events: write
+      actions: read
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Set up Node.js 20.x
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: npm
+
+      - name: Install dependencies
+        run: npm ci
+
+      # Use a paths filter (v3) to detect changes in JavaScript/TypeScript files,
+      # but only consider files that are added or modified (ignoring deleted files).
+      - name: Filter changed files for ESLint
+        id: file_filter
+        uses: dorny/paths-filter@v3
+        with:
+          filters: |
+            eslint:
+              - added|modified: '**/*.js'
+              - added|modified: '**/*.jsx'
+              - added|modified: '**/*.ts'
+              - added|modified: '**/*.tsx'
+
+      # Run ESLint only if relevant files have been added or modified.
+      - name: Run ESLint on changed files
+        if: steps.file_filter.outputs.eslint == 'true'
+        env:
+          SARIF_ESLINT_IGNORE_SUPPRESSED: "true"
+        run: |
+          # Extract the base commit SHA from the pull_request event payload.
+          BASE_SHA=$(jq --raw-output .pull_request.base.sha "$GITHUB_EVENT_PATH")
+          echo "Base commit SHA: $BASE_SHA"
+          
+          # List files changed between the base commit and current HEAD,
+          # but only include files that are not deleted (ACMRTUXB: A, C, M, R, T, U, X, B).
+          CHANGED_FILES=$(git diff --name-only --diff-filter=ACMRTUXB "$BASE_SHA" HEAD | grep -E '\.(js|jsx|ts|tsx)$')
+          echo "Files to lint:"
+          echo "$CHANGED_FILES"
+          
+          # Run ESLint on the changed files.
+          npx eslint --no-error-on-unmatched-pattern \
+            --config eslint.config.mjs \
+            --format @microsoft/eslint-formatter-sarif \
+            --output-file eslint-results.sarif $CHANGED_FILES || true
+
+      # If no JavaScript/TypeScript files were added or modified,
+      # create a valid (non-empty) SARIF file containing one run.
+      - name: Create empty SARIF results file
+        if: steps.file_filter.outputs.eslint != 'true'
+        run: |
+          cat << 'EOF' > eslint-results.sarif
+          {
+            "version": "2.1.0",
+            "$schema": "https://json.schemastore.org/sarif-2.1.0.json",
+              "runs": [
+                  {
+                  "tool": {
+                      "driver": {
+            "name": "ESLint",
+            "informationUri": "https://eslint.org",
+            "version": "0.0.0",
+            "rules": []
+          }
+            },
+            "results": []
+              }
+          ]
+          }
+          EOF
+
+      - name: Upload analysis results to GitHub
+        uses: github/codeql-action/upload-sarif@v3
+        with:
+          sarif_file: eslint-results.sarif
+          wait-for-processing: true