diff --git a/src/mimes.ts b/src/mimes.ts
new file mode 100644
index 0000000..a49866d
--- /dev/null
+++ b/src/mimes.ts
@@ -0,0 +1,10 @@
+const extToMimes = new Map(
+  Object.entries({
+    html: "text/html",
+    xhtml: "application/xhtml+xml",
+    xml: "application/xml",
+  })
+);
+Object.freeze(extToMimes);
+
+export default extToMimes;