--- a/devtools/client/netmonitor/webpack.config.js
+++ b/devtools/client/netmonitor/webpack.config.js
@@ -110,19 +110,21 @@ const mappings = [
         .replace("./resource://devtools/client", path.join(__dirname, ".."));
     }
   ],
 ];
 
 webpackConfig.plugins = mappings.map(([regex, res]) =>
   new NormalModuleReplacementPlugin(regex, res));
 
-// Exclude to transplie all scripts in devtools/ but not for this folder
-webpackConfig.babelExcludes = new RegExp(
-  `^${path.join(__dirname, "../../")}(.(?!${path.basename(__dirname)}))*$`);
+// Exclude to transpile all scripts in devtools/ but not for this folder
+const basePath = path.join(__dirname, "../../").replace(/\\/g, "\\\\");
+const baseName = path.basename(__dirname);
+webpackConfig.babelExcludes = new RegExp(`^${basePath}(.(?!${baseName}))*$`);
+
 let config = toolboxConfig(webpackConfig, getConfig());
 
 // Remove loaders from devtools-launchpad's webpack.config.js
 // * For svg-inline loader:
 //   Netmonitor uses file loader to bundle image assets instead of svg-inline loader
 // * For raw loader:
 //   devtools/shared/l10n has preloaded raw loader in require.context
 config.module.loaders = config.module.loaders