From 9477ff886fa2c4e5fa26d123503922e532a8ca37 Mon Sep 17 00:00:00 2001
From: Vladimir Pouzanov <farcaller@google.com>
Date: Sun, 31 Dec 2017 10:10:52 +0000
Subject: [PATCH] Bubble up errors from webpack run

---
 .../gatsby/src/commands/build-javascript.js     | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/packages/gatsby/src/commands/build-javascript.js b/packages/gatsby/src/commands/build-javascript.js
index 842d52ca31a91..9d7bb440fa075 100644
--- a/packages/gatsby/src/commands/build-javascript.js
+++ b/packages/gatsby/src/commands/build-javascript.js
@@ -11,7 +11,20 @@ module.exports = async program => {
     `build-javascript`
   )
 
-  return new Promise(resolve => {
-    webpack(compilerConfig.resolve()).run(() => resolve())
+  return new Promise((resolve, reject) => {
+    webpack(compilerConfig.resolve()).run((err, stats) => {
+      if (err) {
+        reject(err)
+        return
+      }
+
+      const jsonStats = stats.toJson()
+      if (jsonStats.errors && jsonStats.errors.length > 0) {
+        reject(jsonStats.errors[0])
+        return
+      }
+
+      resolve()
+    })
   })
 }