diff --git a/packages/vite/src/node/plugins/css.ts b/packages/vite/src/node/plugins/css.ts
index 09cc44803d8c90..94d7f48e2c6180 100644
--- a/packages/vite/src/node/plugins/css.ts
+++ b/packages/vite/src/node/plugins/css.ts
@@ -1074,6 +1074,8 @@ export async function preprocessCSS(
   return await compileCSS(filename, code, config)
 }
 
+const postcssReturnsVirtualFilesRE = /^<.+>$/
+
 export async function formatPostcssSourceMap(
   rawMap: ExistingRawSourceMap,
   file: string,
@@ -1083,8 +1085,7 @@ export async function formatPostcssSourceMap(
   const sources = rawMap.sources.map((source) => {
     const cleanSource = cleanUrl(decodeURIComponent(source))
 
-    // postcss returns virtual files
-    if (/^<.+>$/.test(cleanSource)) {
+    if (postcssReturnsVirtualFilesRE.test(cleanSource)) {
       return `\0${cleanSource}`
     }
 
diff --git a/packages/vite/src/node/plugins/dynamicImportVars.ts b/packages/vite/src/node/plugins/dynamicImportVars.ts
index f730fc9e093bbf..7933618d49da08 100644
--- a/packages/vite/src/node/plugins/dynamicImportVars.ts
+++ b/packages/vite/src/node/plugins/dynamicImportVars.ts
@@ -19,6 +19,7 @@ import { toAbsoluteGlob } from './importMetaGlob'
 
 export const dynamicImportHelperId = '\0vite/dynamic-import-helper'
 
+const relativePathRE = /^\.{1,2}\//
 interface DynamicImportRequest {
   as?: keyof KnownAsTypeMap
 }
@@ -122,7 +123,7 @@ export async function transformDynamicImport(
     await toAbsoluteGlob(rawPattern, root, importer, resolve),
   )
 
-  if (!/^\.{1,2}\//.test(newRawPattern)) {
+  if (!relativePathRE.test(newRawPattern)) {
     newRawPattern = `./${newRawPattern}`
   }
 
diff --git a/packages/vite/src/node/plugins/esbuild.ts b/packages/vite/src/node/plugins/esbuild.ts
index 55b079577ce679..f12b6cba1b97c0 100644
--- a/packages/vite/src/node/plugins/esbuild.ts
+++ b/packages/vite/src/node/plugins/esbuild.ts
@@ -30,6 +30,9 @@ const INJECT_HELPERS_IIFE_RE =
 const INJECT_HELPERS_UMD_RE =
   /^(.*?)(\(function\([^)]*\)\s*\{.+?amd.+?function\([^)]*\)\s*\{.*?"use strict";)/s
 
+const validExtensionRE = /\.\w+$/
+const jsxExtensionsRE = /\.(?:j|t)sx\b/
+
 let server: ViteDevServer
 
 export interface ESBuildOptions extends TransformOptions {
@@ -75,7 +78,7 @@ export async function transformWithEsbuild(
     // if the id ends with a valid ext, use it (e.g. vue blocks)
     // otherwise, cleanup the query before checking the ext
     const ext = path
-      .extname(/\.\w+$/.test(filename) ? filename : cleanUrl(filename))
+      .extname(validExtensionRE.test(filename) ? filename : cleanUrl(filename))
       .slice(1)
 
     if (ext === 'cjs' || ext === 'mjs') {
@@ -247,7 +250,7 @@ export function esbuildPlugin(options: ESBuildOptions): Plugin {
             this.warn(prettifyMessage(m, code))
           })
         }
-        if (jsxInject && /\.(?:j|t)sx\b/.test(id)) {
+        if (jsxInject && jsxExtensionsRE.test(id)) {
           result.code = jsxInject + ';' + result.code
         }
         return {
diff --git a/packages/vite/src/node/plugins/importAnalysis.ts b/packages/vite/src/node/plugins/importAnalysis.ts
index b18c9c6bc2f511..ec377083a2d688 100644
--- a/packages/vite/src/node/plugins/importAnalysis.ts
+++ b/packages/vite/src/node/plugins/importAnalysis.ts
@@ -78,6 +78,13 @@ export const canSkipImportAnalysis = (id: string): boolean =>
 const optimizedDepChunkRE = /\/chunk-[A-Z\d]{8}\.js/
 const optimizedDepDynamicRE = /-[A-Z\d]{8}\.js/
 
+const hasImportInQueryParamsRE = /[?&]import=?\b/
+
+const hasViteIgnoreRE = /\/\*\s*@vite-ignore\s*\*\//
+
+const cleanUpRawUrlRE = /\/\*[\s\S]*?\*\/|([^\\:]|^)\/\/.*$/gm
+const urlIsStringRE = /^(?:'.*'|".*"|`.*`)$/
+
 export function isExplicitImportRequired(url: string): boolean {
   return !isJSRequest(cleanUrl(url)) && !isCSSRequest(url)
 }
@@ -373,7 +380,7 @@ export function importAnalysisPlugin(config: ResolvedConfig): Plugin {
           // query can break 3rd party plugin's extension checks.
           if (
             (isRelative || isSelfImport) &&
-            !/[?&]import=?\b/.test(url) &&
+            !hasImportInQueryParamsRE.test(url) &&
             !url.match(DEP_VERSION_RE)
           ) {
             const versionMatch = importer.match(DEP_VERSION_RE)
@@ -613,7 +620,7 @@ export function importAnalysisPlugin(config: ResolvedConfig): Plugin {
         } else if (!importer.startsWith(clientDir)) {
           if (!importer.includes('node_modules')) {
             // check @vite-ignore which suppresses dynamic import warning
-            const hasViteIgnore = /\/\*\s*@vite-ignore\s*\*\//.test(
+            const hasViteIgnore = hasViteIgnoreRE.test(
               // complete expression inside parens
               source.slice(dynamicIndex + 1, end),
             )
@@ -637,11 +644,9 @@ export function importAnalysisPlugin(config: ResolvedConfig): Plugin {
           }
 
           if (!ssr) {
-            const url = rawUrl
-              .replace(/\/\*[\s\S]*?\*\/|([^\\:]|^)\/\/.*$/gm, '')
-              .trim()
+            const url = rawUrl.replace(cleanUpRawUrlRE, '').trim()
             if (
-              !/^(?:'.*'|".*"|`.*`)$/.test(url) ||
+              !urlIsStringRE.test(url) ||
               isExplicitImportRequired(url.slice(1, -1))
             ) {
               needQueryInjectHelper = true
diff --git a/packages/vite/src/node/plugins/resolve.ts b/packages/vite/src/node/plugins/resolve.ts
index 9404fdde034ed7..2ba737063df691 100644
--- a/packages/vite/src/node/plugins/resolve.ts
+++ b/packages/vite/src/node/plugins/resolve.ts
@@ -62,6 +62,8 @@ export const optionalPeerDepId = '__vite-optional-peer-dep'
 const nodeModulesInPathRE = /(?:^|\/)node_modules\//
 const subpathImportsPrefix = '#'
 
+const startsWithWordCharRE = /^\w/
+
 const isDebug = process.env.DEBUG
 const debug = createDebugger('vite:resolve-details', {
   onlyWhenFocused: true,
@@ -279,7 +281,8 @@ export function resolvePlugin(resolveOptions: InternalResolveOptions): Plugin {
       // relative
       if (
         id.startsWith('.') ||
-        ((preferRelative || importer?.endsWith('.html')) && /^\w/.test(id))
+        ((preferRelative || importer?.endsWith('.html')) &&
+          startsWithWordCharRE.test(id))
       ) {
         const basedir = importer ? path.dirname(importer) : process.cwd()
         const fsPath = path.resolve(basedir, id)