Xcode + React-native: "Source and image related" build step too long

There's something wrong with my RN app building. Bundle React's "Source and Images" is taking too long.
This single task takes about 10 minutes to complete.

Here's the complete build log

It seems like JS binding takes too long to finish.

Additional Information:

• MacOS Sierra v10.12.5 (Mac mini)
• XCode v8.3.3
• react-native v0.42.3
• npm v3.10.10
• node v6.11.0
• watchman v4.7.0

I tried uninstalling and installing watchman

using homebrew. But the problem continues.