diff --git a/functions/editorutils.js b/functions/editorutils.js
new file mode 100644
index 000000000..c8e14a5f9
--- /dev/null
+++ b/functions/editorutils.js
@@ -0,0 +1,11 @@
+const mimeToMode = {
+  "text/plain": "plain_text",
+  "text/html": "html",
+  "application/xml": "xml",
+  "application/hal+json": "json",
+  "application/json": "json"
+}
+
+export function getEditorLangForMimeType(mimeType) {
+  return mimeToMode[mimeType] || "plain_text";
+}