diff --git a/package.json b/package.json
index 395609e2a..57cba3eb6 100644
--- a/package.json
+++ b/package.json
@@ -50,7 +50,7 @@
     "resolve": "1.5.0",
     "semver": "5.4.1",
     "string-width": "2.1.1",
-    "typescript": "2.6.2",
+    "typescript": "2.7.0-insiders.20171214",
     "typescript-eslint-parser": "11.0.0",
     "unicode-regex": "1.0.1",
     "unified": "6.1.6"
diff --git a/tests/literal-numeric-separator/jsfmt.spec.js b/tests/literal-numeric-separator/jsfmt.spec.js
index 968651cdb..4ef9b45f0 100644
--- a/tests/literal-numeric-separator/jsfmt.spec.js
+++ b/tests/literal-numeric-separator/jsfmt.spec.js
@@ -1 +1 @@
-run_spec(__dirname, ["babylon"]);
+run_spec(__dirname, ["babylon", "typescript"]);
diff --git a/yarn.lock b/yarn.lock
index 000e374e3..157eea657 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -4424,9 +4424,9 @@ typescript-eslint-parser@11.0.0:
     lodash.unescape "4.0.1"
     semver "5.4.1"
 
-typescript@2.6.2:
-  version "2.6.2"
-  resolved "https://registry.yarnpkg.com/typescript/-/typescript-2.6.2.tgz#3c5b6fd7f6de0914269027f03c0946758f7673a4"
+typescript@2.7.0-insiders.20171214:
+  version "2.7.0-insiders.20171214"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-2.7.0-insiders.20171214.tgz#841344ddae5f498a97c0435fcd12860480050e71"
 
 uglify-es@3.0.28:
   version "3.0.28"