From 455f30a7b6401a9ed95942636037b2383c677f3d Mon Sep 17 00:00:00 2001
From: silverwind <me@silverwind.io>
Date: Fri, 25 Sep 2026 07:56:07 +0200
Subject: [PATCH] chore(frontend): target ES2022 (#39420)

Bump the TypeScript and Vite targets from ES2020 to ES2022. The frontend
already calls ES2022 APIs like `Object.hasOwn` and `Array.prototype.at`
without polyfills, so downleveling class syntax only added helpers. JS
output shrinks by 36 KB.

The only new syntax-level requirement is Safari 16.4 for mermaid, which
ships class static blocks. Pale Moon supports all emitted syntax since
32.2.

The ES2022 target implies `useDefineForClassFields`, so
`noImplicitOverride` is enabled to flag class fields that shadow
inherited DOM properties.
---
 tools/eslint-rules/unescaped-html-literal.test.ts | 8 +-------
 tsconfig.json                                     | 3 ++-
 vite.config.ts                                    | 2 +-
 web_src/js/webcomponents/relative-time.ts         | 4 ++--
 4 files changed, 6 insertions(+), 11 deletions(-)

diff --git a/tools/eslint-rules/unescaped-html-literal.test.ts b/tools/eslint-rules/unescaped-html-literal.test.ts
index b2c2ff27421..af3d473e764 100644
--- a/tools/eslint-rules/unescaped-html-literal.test.ts
+++ b/tools/eslint-rules/unescaped-html-literal.test.ts
@@ -4,13 +4,7 @@
 import rule from './unescaped-html-literal.ts';
 import {RuleTester} from 'eslint';
 
-class VitestRuleTester extends RuleTester {
-  static describe = describe;
-  static it = it;
-  static itOnly = it.only;
-}
-
-const ruleTester = new VitestRuleTester();
+const ruleTester = new RuleTester();
 
 ruleTester.run('unescaped-html-literal', rule, {
   valid: [
diff --git a/tsconfig.json b/tsconfig.json
index bcecb172172..41bd533a9d0 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -10,7 +10,7 @@
     "${configDir}/web_src/js/**/.*",
   ],
   "compilerOptions": {
-    "target": "es2020",
+    "target": "es2022",
     "module": "esnext",
     "moduleResolution": "bundler",
     "lib": ["dom", "esnext", "webworker"],
@@ -26,6 +26,7 @@
     "libReplacement": false,
     "noEmit": true,
     "noFallthroughCasesInSwitch": true,
+    "noImplicitOverride": true,
     "noImplicitReturns": true,
     "noUncheckedSideEffectImports": true,
     "noPropertyAccessFromIndexSignature": false,
diff --git a/vite.config.ts b/vite.config.ts
index 1ae9a927402..b4b5538b978 100644
--- a/vite.config.ts
+++ b/vite.config.ts
@@ -61,7 +61,7 @@ function commonViteOpts({build, ...other}: InlineConfig): InlineConfig {
       outDir,
       emptyOutDir: false,
       sourcemap: enableSourcemap !== 'false',
-      target: 'es2020',
+      target: 'es2022',
       minify: isProduction ? 'oxc' : false,
       cssMinify: isProduction ? 'esbuild' : false,
       chunkSizeWarningLimit: Infinity,
diff --git a/web_src/js/webcomponents/relative-time.ts b/web_src/js/webcomponents/relative-time.ts
index e7bff3f5092..ac7bb6cc22c 100644
--- a/web_src/js/webcomponents/relative-time.ts
+++ b/web_src/js/webcomponents/relative-time.ts
@@ -319,11 +319,11 @@ class RelativeTime extends HTMLElement {
     return undefined;
   }
 
-  get prefix(): string {
+  override get prefix(): string {
     return this.getAttribute('prefix') ?? (this.format === 'datetime' ? '' : 'on');
   }
 
-  set prefix(v: string) {
+  override set prefix(v: string) {
     this.setAttribute('prefix', v);
   }