Xcode控制台报错信息：
Assertion failed: (severity >= 0 && severity < NUM_SEVERITIES), function SetLogDestination,
file /Users/z/code/rntest/OldRNDemo/node_modules/react-native/third-party/glog-0.3.4/src/logging.cc, line 595.
解决方法：
cd node_modules/react-native/scripts && ./ios-install-third-party.sh && cd ../../../
再执行
cd node_modules/react-native/third-party/glog-0.3.4/ && ../../scripts/ios-configure-glog.sh && cd ../../../../