Check if there was a redirection in Fish

Question

I'm writing a simple function for fish-shell that should behave like this :

theFunc someArguments
somecommand | theFunc

I looking for a way to know if the function was called with a pipe / redirection or not.
Do you have an idea SO?

Thanks!

Answer 1

I'm setting the informations if anyone needs it.

As Ben Voigt pointed it out, we should use the isatty function.
For fish-shell you can simply check:

if isatty stdin
    # Your code here.
end