diff --git a/compiler/forget/tsconfig.json b/compiler/forget/tsconfig.json
index c9ad93e333..4420706d67 100644
--- a/compiler/forget/tsconfig.json
+++ b/compiler/forget/tsconfig.json
@@ -12,7 +12,8 @@
     "useUnknownInCatchVariables": false,
     "target": "ES2015",
     // ideally turn off only during dev, or on a per-file basis
-    "noUnusedLocals": false
+    "noUnusedLocals": false,
+    "sourceMap": true
   },
   "exclude": ["node_modules"],
   "include": ["src/**/*.ts"]