diff --git a/package.json b/package.json
index feccc807c..c65d91459 100644
--- a/package.json
+++ b/package.json
@@ -170,6 +170,7 @@
   "devDependencies": {
     "@types/archiver": "^3.1.0",
     "@types/bluebird": "^3.5.30",
+    "@types/codemirror": "^0.0.95",
     "@types/diff-match-patch": "^1.0.32",
     "@types/express": "^4.17.6",
     "@types/helmet": "^0.0.45",
diff --git a/tsconfig.json b/tsconfig.json
index 5bff2a5d0..90a04b54c 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -9,7 +9,7 @@
     "experimentalDecorators": true,
     "emitDecoratorMetadata": true,
     "sourceMap": true,
-    "lib": ["ES2019"],
+    "lib": ["ES2019", "DOM"],
     "alwaysStrict": true
   },
   "include":  ["src"]