@@ -0,0 +1,3 @@
+// Regression test: mlly's regex parser incorrectly captures `async` from
+// arrow function bodies as an export name. unimport should filter it out.
+export const useSleep = () => useAsyncData('sleep', async () => { })
@@ -11,6 +11,65 @@ import pm from 'picomatch'
 import { camelCase } from 'scule'
 import { glob } from 'tinyglobby'
 
+// JavaScript reserved words and keywords that mlly's regex parser may
+// incorrectly capture as export names from declaration expressions.
+// See: https://github.com/unjs/unimport/issues/303
+const JS_RESERVED_WORDS = new Set([
+  // Keywords
+  'abstract',
+  'arguments',
+  'async',
+  'await',
+  'break',
+  'case',
+  'catch',
+  'class',
+  'const',
+  'continue',
+  'debugger',
+  'default',
+  'delete',
+  'do',
+  'else',
+  'enum',
+  'eval',
+  'export',
+  'extends',
+  'false',
+  'finally',
+  'for',
+  'function',
+  'if',
+  'implements',
+  'import',
+  'in',
+  'instanceof',
+  'interface',
+  'let',
+  'new',
+  'null',
+  'of',
+  'package',
+  'private',
+  'protected',
+  'public',
+  'return',
+  'static',
+  'super',
+  'switch',
+  'this',
+  'throw',
+  'true',
+  'try',
+  'typeof',
+  'undefined',
+  'var',
+  'void',
+  'while',
+  'with',
+  'yield',
+])
+
 const FileExtensionLookup = [
   'mts',
   'cts',
@@ -139,6 +198,8 @@ export async function scanExports(filepath: string, includeTypes: boolean, seen
       }
       else if (exp.type === 'declaration') {
         for (const name of exp.names) {
+          if (JS_RESERVED_WORDS.has(name))
+            continue
           imports.push({ name, as: name, from: filepath, ...additional })
           if (exp.declarationType === 'enum' || exp.declarationType === 'const enum' || exp.declarationType === 'class') {
             imports.push({ name, as: name, from: filepath, type: true, declarationType: exp.declarationType, ...additional })
 
@@ -96,6 +96,7 @@ it('dts', async () => {
         const useDoubled: typeof import('<root>/playground/composables/index').useDoubled
         const useEffect: typeof import('react').useEffect
         const useRef: typeof import('react').useRef
+        const useSleep: typeof import('<root>/playground/composables/async-value').useSleep
         const useState: typeof import('react').useState
         const vanillaA: typeof import('<root>/playground/composables/vanilla').vanillaA
         const vanillaAMJS: typeof import('<root>/playground/composables/vanilla').vanillaAMJS
 
@@ -1,6 +1,7 @@
 import { join, relative } from 'pathe'
 import { describe, expect, it } from 'vitest'
 import { normalizeScanDirs, scanDirExports, stringifyImports } from '../src'
+import { scanExports } from '../src/node/scan-dirs'
 
 describe('scan-dirs', () => {
   it('scanDirExports', async () => {
@@ -90,6 +91,11 @@ describe('scan-dirs', () => {
             "from": "index.ts",
             "name": "useDoubled",
           },
+          {
+            "as": "useSleep",
+            "from": "async-value.ts",
+            "name": "useSleep",
+          },
           {
             "as": "vanillaA",
             "from": "vanilla.js",
@@ -279,6 +285,17 @@ describe('scan-dirs', () => {
     const singleAsteriskExports = await scanDirExports([dirWithSingleAsterisk])
     expect(singleAsteriskExports.some(i => i.name === 'CustomType2')).toEqual(true)
   })
+
+  it('should not register JS reserved words as exports from declaration expressions', async () => {
+    // mlly's regex parser incorrectly captures `async` from arrow function
+    // bodies (e.g. `export const x = () => foo(async () => {})`) as an export
+    // name. unimport should filter these out.
+    const filepath = join(__dirname, '../playground/composables/async-value.ts')
+    const exports = await scanExports(filepath, false)
+    const names = exports.map(i => i.name)
+    expect(names).toContain('useSleep')
+    expect(names).not.toContain('async')
+  })
 })
 
 it('normalizeScanDirs', () => {
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	+// Regression test: mlly's regex parser incorrectly captures `async` from
	`2`	`+// arrow function bodies as an export name. unimport should filter it out.`
	`3`	`+export const useSleep = () => useAsyncData('sleep', async () => { })`