access window via global in case not defined

Author: justadudewhohacks

lib/opencv4nodejs.js

@@ -5,8 +5,8 @@ const isElectronWebpack =
   // assume module required by webpack if no system path inv envs
   !process.env.path
   // detect if electron https://github.com/electron/electron/issues/2288
-  && window && window.process && window.process.type
-  && navigator && ((navigator.userAgent || '').toLowerCase().indexOf(' electron/') > -1)
+  && global.window && global.window.process && global.window.process.type
+  && global.navigator && ((global.navigator.userAgent || '').toLowerCase().indexOf(' electron/') > -1)
 
 let cv = isElectronWebpack ? require('../build/Release/opencv4nodejs.node') : require('./cv')