Wrapped the config parameters inside if statement as they may be undefined

webpack.config.ts

@@ -86,10 +86,14 @@ const config: Configuration = {
 
 if (process.env.NODE_ENV === "production") {
   config.mode = "production";
-  config.output.filename = "[name]-bundle-[hash].min.js";
-  config.output.chunkFilename = "[name]-chunk-[chunkhash].min.js";
-  config.optimization.chunkIds = "deterministic";
-  config.optimization.minimize = true;
+  if (config.output) {
+    config.output.filename = '[name]-bundle-[hash].min.js';
+    config.output.chunkFilename = '[name]-chunk-[chunkhash].min.js';
+  }
+  if (config.optimization) {
+    config.optimization.chunkIds = 'deterministic';
+    config.optimization.minimize = true;
+  }
   config.devtool = false;
 }