feat(node): add support for async webpack configuration (#9641)

docs/shared/guides/customize-webpack.md

@@ -21,6 +21,20 @@ module.exports = (config, context) => {
 };
 ```
 
+Also supports promises
+
+```typescript
+// Utility function for sleeping
+const sleep = (n) => new Promise((resolve) => setTimeout(resolve, n));
+
+module.exports = async (config, context) => {
+  await sleep(10);
+  return merge(config, {
+    // overwrite values here
+  });
+};
+```
+
 ## Add a Loader
 
 To add the `css-loader` to your config, install it and add the rule.

packages/node/src/executors/webpack/webpack.impl.ts

@@ -81,12 +81,15 @@ export async function* webpackExecutor(
   if (options.generatePackageJson) {
     generatePackageJson(context.projectName, projGraph, options);
   }
-  const config = options.webpackConfig.reduce((currentConfig, plugin) => {
-    return require(plugin)(currentConfig, {
-      options,
-      configuration: context.configurationName,
-    });
-  }, getNodeWebpackConfig(options));
+  const config = await options.webpackConfig.reduce(
+    async (currentConfig, plugin) => {
+      return require(plugin)(await currentConfig, {
+        options,
+        configuration: context.configurationName,
+      });
+    },
+    Promise.resolve(getNodeWebpackConfig(options))
+  );
 
   return yield* eachValueFrom(
     runWebpack(config).pipe(