What exactly does the anonymous JavaScript function f => f do?

Question

I\'m using a third-party library that has a function that takes functions as arguments. I\'m doing some conditional checks to decide whether or not to add a particular funct

Answer 1

Others have already mentioned what f => f does, so I'm not going to go deeper into that. I'm just going to explain the rest of the function, because there's a bit of a difference between f => f and __DEV__ ? devTools() : f => f

The ternary operator checks if __DEV__ is a truthy value, and if so, it return function devTools(). otherwise, it return the identity function f => f which does nothing. Put differently: this code enables some development mode functions. Without the remaining code, it's hard to tell what this mode adds, but presumably, it will enable some extra logging information and less obfuscation.