Remove unused dependencies and symbols using knip

Author: sandhose

.github/workflows/ci.yaml

@@ -98,6 +98,31 @@ jobs:
         run: npm test
 
 
+  frontend-knip:
+    name: Check the frontend for unused dependencies
+    runs-on: ubuntu-latest
+
+    permissions:
+      contents: read
+
+    steps:
+      - name: Checkout the code
+        uses: actions/[email protected]
+
+      - name: Install Node
+        uses: actions/[email protected]
+        with:
+          node-version: 20
+
+      - name: Install Node dependencies
+        working-directory: ./frontend
+        run: npm ci
+
+      - name: Check for unused dependencies
+        working-directory: ./frontend
+        run: npm run knip
+
+
   rustfmt:
     name: Check Rust style
     runs-on: ubuntu-latest
@@ -362,6 +387,7 @@ jobs:
       - opa-lint
       - frontend-lint
       - frontend-test
+      - frontend-knip
       - rustfmt
       - cargo-deny
       - clippy

frontend/i18next-parser.config.ts

@@ -6,7 +6,7 @@
 
 import type { UserConfig } from "i18next-parser";
 
-const config: UserConfig = {
+export default {
   keySeparator: ".",
   pluralSeparator: ":",
   defaultNamespace: "frontend",
@@ -30,6 +30,4 @@ const config: UserConfig = {
   output: "locales/$LOCALE.json",
   input: ["src/**/*.{ts,tsx}"],
   sort: true,
-};
-
-export default config;
+} satisfies UserConfig;

frontend/knip.config.ts

@@ -0,0 +1,22 @@
+// Copyright 2024 New Vector Ltd.
+//
+// SPDX-License-Identifier: AGPL-3.0-only
+// Please see LICENSE in the repository root for full details.
+
+import type { KnipConfig } from "knip";
+
+export default {
+  entry: [
+    "src/main.tsx",
+    "src/swagger.tsx",
+    "src/routes/*",
+    "i18next-parser.config.ts",
+  ],
+  ignore: ["src/gql/*", "src/routeTree.gen.ts", ".storybook/locales.ts"],
+  ignoreDependencies: [
+    // This is used by the tailwind PostCSS plugin, but not detected by knip
+    "postcss-nesting",
+    // We're using @storybook/addon-essentials to simplify upgrades, but knip doesn't detect them
+    "@storybook/addon-*",
+  ],
+} satisfies KnipConfig;