build: clean generated type file (vitejs#14582)

packages/vite/rollup.dts.config.ts

@@ -1,5 +1,6 @@
 import { readFileSync } from 'node:fs'
 import { fileURLToPath } from 'node:url'
+import { findStaticImports } from 'mlly'
 import { type Plugin, defineConfig } from 'rollup'
 import dts from 'rollup-plugin-dts'
 
@@ -28,12 +29,34 @@ const multilineCommentsRE = /\/\*[^*]*\*+(?:[^/*][^*]*\*+)*\//g
 const singlelineCommentsRE = /\/\/[^/].*/g
 const licenseCommentsRE = /MIT License|MIT license|BSD license/
 const consecutiveNewlinesRE = /\n{2,}/g
+const identifierWithTrailingDollarRE = /\b(\w+)\$\d+\b/g
+
+/**
+ * Replace specific identifiers with a more readable name, grouped by
+ * the module that imports the identifer as a named import alias
+ */
+const identifierReplacements: Record<string, Record<string, string>> = {
+  rollup: {
+    Plugin$1: 'rollup.Plugin',
+    TransformResult$2: 'rollup.TransformResult',
+  },
+  esbuild: {
+    TransformResult$1: 'esbuild_TransformResult',
+    TransformOptions$1: 'esbuild_TransformOptions',
+    BuildOptions$1: 'esbuild_BuildOptions',
+  },
+  'node:https': {
+    Server$1: 'HttpsServer',
+    ServerOptions$1: 'HttpsServerOptions',
+  },
+}
 
 /**
  * Patch the types files before passing to dts plugin
  * 1. Resolve `dep-types/*` and `types/*` imports
  * 2. Validate unallowed dependency imports
- * 3. Clean unnecessary comments
+ * 3. Replace confusing type names
+ * 4. Clean unnecessary comments
  */
 function patchTypes(): Plugin {
   return {
@@ -56,8 +79,8 @@ function patchTypes(): Plugin {
       }
     },
     renderChunk(code, chunk) {
-      const deps = new Set(Object.keys(pkg.dependencies))
       // Validate that chunk imports do not import dev deps
+      const deps = new Set(Object.keys(pkg.dependencies))
       for (const id of chunk.imports) {
         if (
           !id.startsWith('./') &&
@@ -72,13 +95,79 @@ function patchTypes(): Plugin {
         }
       }
 
+      // Rollup deduplicate type names with a trailing `$1` or `$2`, which can be
+      // confusing when showed in autocompletions. Try to replace with a better name
+      const imports = findStaticImports(code)
+      for (const modName in identifierReplacements) {
+        const imp = imports.find(
+          (imp) => imp.specifier === modName && imp.imports.includes('{'),
+        )
+        // Validate that `identifierReplacements` is not outdated if there's no match
+        if (!imp) {
+          this.warn(
+            `${chunk.fileName} does not import "${modName}" for replacement`,
+          )
+          process.exitCode = 1
+          continue
+        }
+
+        const replacements = identifierReplacements[modName]
+        for (const id in replacements) {
+          // Validate that `identifierReplacements` is not outdated if there's no match
+          if (!imp.imports.includes(id)) {
+            this.warn(
+              `${chunk.fileName} does not import "${id}" from "${modName}" for replacement`,
+            )
+            process.exitCode = 1
+            continue
+          }
+
+          const betterId = replacements[id]
+          const regexEscapedId = escapeRegex(id)
+          // If the better id accesses a namespace, the existing `Foo as Foo$1`
+          // named import cannot be replaced with `Foo as Namespace.Foo`, so we
+          // pre-emptively remove the whole named import
+          if (betterId.includes('.')) {
+            code = code.replace(
+              new RegExp(`\\b\\w+\\b as ${regexEscapedId},?\\s?`),
+              '',
+            )
+          }
+          code = code.replace(
+            new RegExp(`\\b${regexEscapedId}\\b`, 'g'),
+            betterId,
+          )
+        }
+      }
+      const unreplacedIds = unique(
+        Array.from(code.matchAll(identifierWithTrailingDollarRE), (m) => m[0]),
+      )
+      if (unreplacedIds.length) {
+        const unreplacedStr = unreplacedIds.map((id) => `\n- ${id}`).join('')
+        this.warn(
+          `${chunk.fileName} contains confusing identifier names${unreplacedStr}`,
+        )
+        process.exitCode = 1
+      }
+
       // Clean unnecessary comments
-      return code
+      code = code
         .replace(singlelineCommentsRE, '')
         .replace(multilineCommentsRE, (m) => {
           return licenseCommentsRE.test(m) ? '' : m
         })
         .replace(consecutiveNewlinesRE, '\n\n')
+
+      return code
     },
   }
 }
+
+const escapeRegexRE = /[-/\\^$*+?.()|[\]{}]/g
+function escapeRegex(str: string): string {
+  return str.replace(escapeRegexRE, '\\$&')
+}
+
+function unique<T>(arr: T[]): T[] {
+  return Array.from(new Set(arr))
+}