Check if a variable is of the function type

Question

Let’s say I have some variable, defined as:

var xpto = function() {/* Faz alguma coisa */};

I need to compare if the type of the variable is a function, ie:

function isFunction(f) {if (f is (function type?)) {/* ... */}};
isFunction(xpto);

So how can I check whether the variable xpto is the type function?

Answer 1

Knowing that:

typeof xpto // "function"

Maybe do:

function isFunction(f) {
  return (typeof f === "function")
}

Be an option for what you want. I hope I’ve helped.

Answer 2

Darlei, for that there is the function typeof javascript.

See a small example:

let fun = () => {
  console.log("É uma função");
}

if (typeof(fun) == "function") {
  console.log("É uma função! =)")
}

Reference: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/typeof