How to Print Function Signature in javascript

Question

I have a function:

fs.readFile = function(filename, callback) {
    // implementation code.
};

Sometime later I want to see the signature of th

Answer 1

If what you mean by "function signature" is how many arguments it has defined, you can use:

function fn (one) {}
console.log(fn.length); // 1

All functions get a length property automatically.