how to write function inside function in javascript code example

Example: function inside function javascript

function getFullName() {
	return getName() + ' ' + getLastName();
  	function getName() {
    	return 'William';
    }
  	function getLastName() {
    	return 'Wallace';
    }
}

console.log(getFullName());
//William Wallace
console.log(typeof getFullName);
//function
console.log(typeof getName);
//undefined
console.log(typeof getLastName);
//undefined