Special characters are not storing in external JS file

I have a global variable globalTXT = ‘gefülltes’; in language.js file
and When I do console.log(globalTXT) then ? appears showing that this special character is not supported

I want to use globalTXT variable text in textObject. It works fine if I set the value through JS event in event editor but not works in external file language.js

may be character problem .
How can It be fixed???

Have you checked the encoding of your javascript file ? It needs to be encoded in UTF8.

Gdevelop JS editor is not saving the files in UTF-8 character encoding.
After compilation of files I open the file language.js with sublime text editor and then save it with character encoding UTF-8 now the problem is solved.
Please fix this problem in JS editor