React-native: watchman--no-pretty get-sockname returned with exit code null

I follow the starter guide from react native page. Upon run the command react-native run-ios I got the following error:

watchman--no-pretty get-sockname returned with exit code null dyld: Library not loaded: /usr/local/opt/pcre/lib/libpcre.1.dylib
  Referenced from: /usr/local/Cellar/watchman/4.5.0/libexec/bin/watchman
  Reason: image not found

 ERROR  watchman--no-pretty get-sockname returned with exit code null dyld: Library not loaded: /usr/local/opt/pcre/lib/libpcre.1.dylib
  Referenced from: /usr/local/Cellar/watchman/4.5.0/libexec/bin/watchman
  Reason: image not found

Error: watchman--no-pretty get-sockname returned with exit code null dyld: Library not loaded: /usr/local/opt/pcre/lib/libpcre.1.dylib
  Referenced from: /usr/local/Cellar/watchman/4.5.0/libexec/bin/watchman
  Reason: image not found

my system: macos 10.11.6, node 6.2.2