Cannot read property 'split' of undefined

[ishitatsuyuki]

I'm getting multiple error reports from Sentry, which tracks down to the following line:

mapbox-gl-language/index.js

Line 198 in c69b4da

var parts = language.split('-');

All of them are reported from Chrome on Android, where the one with the newest version is running Chrome 62.

[andrewharvey]

I guess it should have a fallback that if it can't get navigator.languages, navigator.language or navigator.userLanguage it should just return null.

[andrewharvey]

BTW. I tested this on Chrome on Android, 69 and I can't replicate, but I still agree with being more defensive in the code.