How can I debug variable of [Function] type?

Question

Some functions are set into variables. And I want to debug what kind of function is set there? However that function can non be changed. In this situation, how should I debug?

var something = returnfunc(); //returnfunc() return function type object
console.log(something);

[Function]

Answer 1

You can call toString in the function to get a string representation of the source code ;)

E.g.:

let fn = (a, b) => a + b; 
console.log(fn.toString())
// (a, b) => a + b