write stats report,json into .embark

lib/pipeline/webpackProcess.js

@@ -96,18 +96,48 @@ class WebpackProcess extends ProcessWrapper {
       };
     }
 
-    webpack(webpackOptions).run((err, stats) => {
-      if (err) {
-        console.error(err);
-      }
-      if (!detectErrors) {
-        return callback();
       }
 
-      if (stats.hasErrors()) {
+    webpack(webpackOptions).run((err, stats) => {
-        return callback(stats.toJson().errors.join("\n"));
+      async.waterfall([
+        function checkStatsError(next) {
+          if (err) {
+            console.error(err);
+            return next(err);
           }
-      callback();
+          if (!detectErrors) {
+            return next();
+          }
+          if (stats.hasErrors()) {
+            return next(
+              stats.toJson(webpackOptions.stats).errors.join("\n")
+            );
+          }
+          next();
+        },
+        function writeStatsReport(next) {
+          if (detectErrors) {
+            self._log('info', 'writing file '+ ('dist/stats.report').bold.dim);
+          }
+          fs.writeFile(
+            path.join(fs.dappPath('.embark'), 'stats.report'),
+            stats.toString(webpackOptions.stats),
+            next
+          );
+        },
+        function writeStatsJSON(next) {
+          if (detectErrors) {
+            self._log('info','writing file '+ ('dist/stats.json').bold.dim);
+          }
+          fs.writeFile(
+            path.join(fs.dappPath('.embark'), 'stats.json'),
+            JSON.stringify(stats.toJson(webpackOptions.stats)),
+            next
+          );
+        }
+      ], (err) => {
+        callback(err);
+      });
     });
   }
 }