how do i see what a function returns code example

Example 1: function and returns node js

function hello(name) {
     console.log("hello " + name);
}
hello("CSS");
//hello CSS

Example 2: what does return do in javascript

function add(a, b) {
  return a + b; //Return stops the execution of this function
}

var sum = add(5, 24); //The value that was returned got but inside the variable sum