From 50c19ca1c2a0423f3f8ff778c0aa5977bafdcc2f Mon Sep 17 00:00:00 2001
From: Kyle Herock <kherock@gmail.com>
Date: Mon, 2 May 2022 22:57:10 -0400
Subject: [PATCH] perf: optimize URL constructors with relative paths

---
 .../playground/worker/worker/main-module.js   |  2 +-
 .../src/node/plugins/assetImportMetaUrl.ts    | 58 ++++++++++++-------
 .../src/node/plugins/workerImportMetaUrl.ts   | 22 +++++--
 3 files changed, 54 insertions(+), 28 deletions(-)

diff --git a/packages/playground/worker/worker/main-module.js b/packages/playground/worker/worker/main-module.js
index 756ece90326d0f..bd0cf2e0fd4b0f 100644
--- a/packages/playground/worker/worker/main-module.js
+++ b/packages/playground/worker/worker/main-module.js
@@ -80,7 +80,7 @@ w.addEventListener('message', (ev) =>
 
 // url import worker with alias path
 const wResolve = new Worker(
-  new URL('@/url-worker', import.meta.url),
+  new URL('@/url-worker.js', import.meta.url),
   /* @vite-ignore */ workerOptions
 )
 wResolve.addEventListener('message', (ev) =>
diff --git a/packages/vite/src/node/plugins/assetImportMetaUrl.ts b/packages/vite/src/node/plugins/assetImportMetaUrl.ts
index a101f7d65e3d74..369bebe8aa7f0e 100644
--- a/packages/vite/src/node/plugins/assetImportMetaUrl.ts
+++ b/packages/vite/src/node/plugins/assetImportMetaUrl.ts
@@ -1,10 +1,11 @@
 import type { Plugin } from '../plugin'
 import MagicString from 'magic-string'
+import path from 'path'
 import { fileToUrl } from './asset'
 import type { ResolvedConfig } from '../config'
 import { emptyString } from '../cleanString'
 import type { ResolveFn } from '../'
-import { isParentDirectory, normalizePath } from '../utils'
+import { isParentDirectory, normalizePath, slash } from '../utils'
 
 /**
  * Convert `new URL('./foo.png', import.meta.url)` to its resolved built URL
@@ -17,6 +18,7 @@ import { isParentDirectory, normalizePath } from '../utils'
  * ```
  */
 export function assetImportMetaUrlPlugin(config: ResolvedConfig): Plugin {
+  const normalizedPublicDir = normalizePath(config.publicDir)
   let assetResolver: ResolveFn
 
   return {
@@ -65,31 +67,45 @@ export function assetImportMetaUrlPlugin(config: ResolvedConfig): Plugin {
           }
 
           const url = rawUrl.slice(1, -1)
-          assetResolver ??= config.createResolver({
-            root: config.publicDir,
-            extensions: [],
-            mainFields: [],
-            tryIndex: false,
-            preferRelative: true
-          })
-          const resolved = await assetResolver(url, id)
-          if (!resolved) {
+          let file: string | undefined
+          if (url.startsWith('.')) {
+            file = slash(path.resolve(path.dirname(id), url))
+          } else {
+            assetResolver ??= config.createResolver({
+              extensions: [],
+              mainFields: [],
+              tryIndex: false,
+              preferRelative: true
+            })
+            file = await assetResolver(url, id)
+            file ??= url.startsWith('/')
+              ? slash(path.join(config.publicDir, url))
+              : slash(path.resolve(path.dirname(id), url))
+          }
+
+          // Get final asset URL. If the file does not exist,
+          // we fall back to the initial URL and let it resolve in runtime
+          let builtUrl: string | undefined
+          if (file) {
+            try {
+              if (isParentDirectory(normalizedPublicDir, file)) {
+                const publicPath =
+                  '/' + path.posix.relative(normalizedPublicDir, file)
+                builtUrl = await fileToUrl(publicPath, config, this)
+              } else {
+                builtUrl = await fileToUrl(file, config, this)
+              }
+            } catch {
+              // do nothing, we'll log a warning after this
+            }
+          }
+          if (!builtUrl) {
             const rawExp = code.slice(index, index + exp.length)
             config.logger.warnOnce(
               `\n${rawExp} doesn't exist at build time, it will remain unchanged to be resolved at runtime`
             )
+            builtUrl = url
           }
-          // Get final asset URL. If the file does not exist,
-          // we fall back to the initial URL and let it resolve in runtime
-          const builtUrl = resolved
-            ? await fileToUrl(
-                isParentDirectory(normalizePath(config.publicDir), resolved)
-                  ? url
-                  : resolved,
-                config,
-                this
-              )
-            : url
           s.overwrite(
             index,
             index + exp.length,
diff --git a/packages/vite/src/node/plugins/workerImportMetaUrl.ts b/packages/vite/src/node/plugins/workerImportMetaUrl.ts
index 08f1b989f727fe..5e1115d1fb8c27 100644
--- a/packages/vite/src/node/plugins/workerImportMetaUrl.ts
+++ b/packages/vite/src/node/plugins/workerImportMetaUrl.ts
@@ -1,8 +1,9 @@
 import JSON5 from 'json5'
+import path from 'path'
 import type { ResolvedConfig } from '../config'
 import type { Plugin } from '../plugin'
 import { fileToUrl } from './asset'
-import { injectQuery } from '../utils'
+import { injectQuery, slash } from '../utils'
 import { workerFileToUrl } from './worker'
 import { parseRequest } from '../utils'
 import { ENV_ENTRY, ENV_PUBLIC_PATH } from '../constants'
@@ -145,11 +146,20 @@ export function workerImportMetaUrlPlugin(config: ResolvedConfig): Plugin {
             index + allExp.length
           )
           const url = rawUrl.slice(1, -1)
-          workerResolver ??= config.createResolver({
-            tryIndex: false,
-            preferRelative: true
-          })
-          const file = (await workerResolver(url, id)) ?? url
+          let file: string | undefined
+          if (url.startsWith('.')) {
+            file = path.resolve(path.dirname(id), url)
+          } else {
+            workerResolver ??= config.createResolver({
+              extensions: [],
+              tryIndex: false,
+              preferRelative: true
+            })
+            file = await workerResolver(url, id)
+            file ??= url.startsWith('/')
+              ? slash(path.join(config.publicDir, url))
+              : slash(path.resolve(path.dirname(id), url))
+          }
 
           let builtUrl: string
           if (isBuild) {