Front end? Smalltalk is there.
Back end? Smalltalk is there.
Desktop? Smalltalk is there.
Mobile? Smalltalk is there.
Natural language processing? Smalltalk is there.
Internet of Things? Smalltalk is there.
Desktop? Check the enterprise and you’ll find that Java and C++ utterly dominate. Electron is but a radar blip.
Mobile? Java/Kotlin and Objective-C/Swift (and even C++!!!) utterly dominate.
Numerical computing? Don’t make me laugh.