diff --git a/demo-shell/tsconfig.json b/demo-shell/tsconfig.json
index d2b9f36445..1788944bcf 100644
--- a/demo-shell/tsconfig.json
+++ b/demo-shell/tsconfig.json
@@ -9,6 +9,7 @@
     "moduleResolution": "node",
     "emitDecoratorMetadata": true,
     "experimentalDecorators": true,
+    "strict": true,
     "skipLibCheck": true,
     "noUnusedLocals": true,
     "noUnusedParameters": true,
diff --git a/lib/tsconfig.json b/lib/tsconfig.json
index 5b6800c499..eca99371ee 100644
--- a/lib/tsconfig.json
+++ b/lib/tsconfig.json
@@ -10,6 +10,7 @@
         "noLib": false,
         "allowUnreachableCode": false,
         "allowUnusedLabels": false,
+        "strict": true,
         "noUnusedParameters": true,
         "noUnusedLocals": true,
         "noImplicitAny": false,
diff --git a/tsconfig.json b/tsconfig.json
index ea92770d79..36ee529d53 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -8,6 +8,7 @@
     "moduleResolution": "node",
     "emitDecoratorMetadata": true,
     "experimentalDecorators": true,
+    "strict": true,
     "skipLibCheck": true,
     "noUnusedLocals": true,
     "noUnusedParameters": true,