Variabler i scope

var-scope.js

function apa1() {
  var david = 'david';
  console.log('%s', david);

}
apa1(); // david

function apa2() {
  var david = 'david';
  console.log('%s, %s', david, petter);
  return;
  var petter;
}
apa2(); // david, undefined

function apa3() {
  var david = 'david';
  console.log('%s, %s, %s', david, petter, urban);
  return;
  var petter, urban = 'urban';
}
apa3(); // david, undefined, undefined

function apa4() {
  var david = 'david';
  console.log('%s, %s, %s, %s', david, petter, urban, ingen);
  return;
  var petter, urban = 'urban';
}
try {
  apa4(); // ReferenceError på "ingen"
}
catch (e) {
  console.log('apa4() => %s', e.message);
}


function apa5() {
  console.log(inner_fd());
  return;
  function inner_fd() {
    return 'a function declaration';
  }
}
apa5(); // works, inner_fd is hoisted


function apa6() {
  console.log('==>'+inner_fd());
  console.log('==>'+inner_fe);
  return;
  function inner_fd() {
	return 'a function declaration';
  }
  var inner_fe = function () {
    return 'a function expression';
  }
}
apa6(); // inner_fd works, inner_fe CAN BE REFERENCED


function apa7() {
  console.log('==>'+inner_fd());
  console.log('==>'+inner_fe);
  console.log('==>'+inner_fe());
  return;
  function inner_fd() {
	return 'a function declaration';
  }
  var inner_fe = function () {
    return 'a function expression';
  }
}
try {
  apa7(); // // inner_fd works, inner_fe can be referenced, but is not initialized and cannot be called (is undefined)
}
catch(e) {
  console.log('apa7 => %s', e.message);
}