Where does undefined comes from?

Question

Consider:

var a = {
   eat: function () {
       console.log('aa')
   }
}
var b = Object.create(a);
console.log(b.eat());

The output of that lines in Chrome is following

aa script.js:3
undefined script.js:7

First line is obvious, but where does second line of output, "undefined", comes from ?

Answer 1

You are trying to log the return value of the eat method, but it does not have a return statement so an undefined value is logged instead.

Answer 2

while b.eat() function is executing its log the the value "aa" but its has nothing to return so returning undefined

try to return something from function to avoid undefined