I have just spent several hours trying to figure out what is wrong with my newly created application.
Error: Argument [...] is not a function, got undefined
It turns out that problem... can be anywhere.
It usually means we have forgotten about some braces, colons, semicolons, commas, dots etc. In short, there is a syntax error.
But I have been reading my code very carefully and there was no mistake.
What worked for me?