diff --git a/server/dts_walker.go b/server/dts_walker.go
index 695a1ed89..7a6e2cbc8 100644
--- a/server/dts_walker.go
+++ b/server/dts_walker.go
@@ -9,7 +9,7 @@ import (
 )
 
 var (
-	regexpImportExportExpr  = regexp.MustCompile(`^(import|export)\s*(type\s*)?('|"|\*|\{)`)
+	regexpImportExportExpr  = regexp.MustCompile(`^(import|export)(\s+type)?\s*('|"|[a-zA-Z0-9_\$]+\s+from|\*|\{)`)
 	regexpFromExpr          = regexp.MustCompile(`(\}|\*|\s)from\s*('|")`)
 	regexpImportPathExpr    = regexp.MustCompile(`^import\s*('|")`)
 	regexpImportCallExpr    = regexp.MustCompile(`(import|require)\(('|").+?('|")\)`)
diff --git a/test/issue-642/issue-642.test.ts b/test/issue-642/issue-642.test.ts
new file mode 100644
index 000000000..a8ff5e717
--- /dev/null
+++ b/test/issue-642/issue-642.test.ts
@@ -0,0 +1,21 @@
+import {
+  assertEquals,
+  assertStringIncludes,
+} from "https://deno.land/std@0.180.0/testing/asserts.ts";
+
+const { version } = await fetch("http://localhost:8080/status.json").then(
+  (r) => r.json(),
+);
+
+Deno.test("issue #642", async () => {
+  const res = await fetch(
+    `http://localhost:8080/v${version}/async-mutex@0.4.0/lib/Mutex.d.ts`,
+    { redirect: "manual" },
+  );
+  assertEquals(res.status, 200);
+  assertEquals(
+    res.headers.get("content-type")!,
+    "application/typescript; charset=utf-8",
+  );
+  assertStringIncludes(await res.text(), "./MutexInterface.d.ts");
+});