fixes #6698

6698: Longstanding issues with the build system

dev_mode/webpack.config.js

@@ -220,7 +220,8 @@ module.exports = [
         });
         ignoreCache[localPath] = ignore;
         return ignore;
-      }
+      },
+      poll: 100
     },
     node: {
       fs: 'empty'

jupyterlab/staging/webpack.config.js

@@ -220,7 +220,8 @@ module.exports = [
         });
         ignoreCache[localPath] = ignore;
         return ignore;
-      }
+      },
+      poll: 100
     },
     node: {
       fs: 'empty'

tsconfigbase.json

@@ -13,6 +13,7 @@
     "noUnusedLocals": true,
     "preserveWatchOutput": true,
     "resolveJsonModule": true,
+    "sourceMap": true,
     "target": "es2017",
     "types": []
   }