javascript - What is the function constructor in Node.js? -

in browser (chrome @ least) functions instances of function

settimeout instanceof function // true 

however in node, not

settimeout instanceof function // false 

so settimeout's constructor if not function?

it seems constructor function, 1 realm.

if run code

console.log(object.getownpropertynames(settimeout.constructor.prototype)); 

you array typical function.prototype methods call, apply , bind.

so guess it's analogous happens in web browsers when borrow settimeout iframe:

var iframe = document.createelement('iframe'); document.body.appendchild(iframe); var win = iframe.contentwindow; console.log(win.settimeout instanceof function);     // false console.log(win.settimeout instanceof win.function); // true