test: tsconfig file for karma with esnext enabled

karma.conf.cjs

@@ -23,7 +23,10 @@ module.exports = function (config) {
         rules: [
           {
             test: /\.(js|tsx?)$/,
-            use: "ts-loader",
+            use: [{
+              loader: 'ts-loader',
+              options: { configFile: 'tsconfig.karma.json' }
+            }],
             exclude: /(node_modules)|(node\.spec\.ts)/,
           },
           {
@@ -44,6 +47,7 @@ module.exports = function (config) {
         extensions: [".ts", ".js"],
       },
       stats: { warnings: false },
+      devtool: 'inline-source-map'
     },
   });
 };

tsconfig.karma.json

@@ -0,0 +1,6 @@
+{
+  "extends": "./tsconfig.dev",
+  "compilerOptions": {
+    "noEmit": false
+  }
+}