React Native depends on on uglify-js@^2.6.2 and as per facebook/react-native#12772 we have run into this error:

uglifyjs@2.8.5:

e.runInContext=n

uglifyjs@2.8.8:

r.runInContext=runInContext

runInContext is undefined in JSC, where react-native runs.

I know very little about uglify-js but posting this here in hopes that you folks may have a better idea of what the problem is.