lang.js: that[ languageCode ].dir is undefined

[Tom Elssjö]

After line 53 in file core/lang.js the following code is found:

that[ languageCode ].dir = that.rtl[ languageCode ] ? 'rtl' : 'ltr';

This fails because that[ languageCode ] have not been defined yet. This can be fixed by adding:

if(!that[ languageCode ]) {
					that[ languageCode ] = {};
				}

before that.

[Jakub Ś]

This fails because that[ languageCode ] have not been defined yet.

Thanks for the solution but you have forgotten to provide the configuration or test case in which editor fails.
When loading editor or changing languages, I can't see any errors being thrown. What are the exact actions, I need to perform, to get this error thrown?