diff --git a/.gitignore b/.gitignore
index 8fd12ce..4f582f1 100644
--- a/.gitignore
+++ b/.gitignore
@@ -114,3 +114,6 @@ dist
 .yarn/unplugged
 .yarn/build-state.yml
 .pnp.*
+
+# TypeScript build output
+lib
diff --git a/jest.config.js b/jest.config.js
index 08e581c..4fe8598 100644
--- a/jest.config.js
+++ b/jest.config.js
@@ -1,3 +1,4 @@
 module.exports = {
   preset: "ts-jest",
+  testEnvironment: "jsdom"
 };
diff --git a/package.json b/package.json
index 956640d..fabb412 100644
--- a/package.json
+++ b/package.json
@@ -27,10 +27,10 @@
   "devDependencies": {
     "@testing-library/preact": "^2.0.0",
     "@types/jest": "^25.2.2",
-    "jest": "^25",
+    "jest": "^27.0.6",
     "preact": "^10.4.8",
     "rimraf": "^3.0.2",
-    "ts-jest": "^25.5.1",
+    "ts-jest": "^27.0.3",
     "typescript": "^3.9.2"
   },
   "peerDependencies": {