meetup.js

// =================== Scope ======================= //

for (var i = 0; i < 5; i++) {
  setTimeout(function() {
    console.log(i);
  }, 2000);
}

-----------------------------------------------------
  
for (var i = 0; i < 5; i++) {
  (function(i) {
    setTimeout(function() {
      console.log(i);
    }, 2000);
  })(i);
}

// =================== XXXXXX ======================= //


// =================== Closure ======================= //

function outerFunction() {
  var count = 10;

  return function innerFunction() {
    console.log(count);
  };
}
var result = outerFunction();

result();

-----------------------------------------------------
function outerFunction() {
  var count = 10;

  return function innerFunction() {
    console.log(count);
  };
}
var result = outerFunction();

console.dir(result);
-----------------------------------------------------
function outerFunction() {
  var count = 10;

  return function innerFunction() {
    console.log("I do nothing");
  };
}
var result = outerFunction();

console.dir(result);

-----------------------------------------------------
  
function foo() {
  var count = 40;
  bar(function() {
    console.log(count);
  });
}

function bar(fun) {
  console.dir(fun);
  fun();
}

foo();

-----------------------------------------------------
  
function foo() {
  var count = 40;
  bar(function() {
    console.log(count);
  });
  count = 50;
}

function bar(fun) {
  console.dir(fun); // Closure scope has value 50;
  fun();
}

foo();

-----------------------------------------------------
  
function foo() {
  var count = 40;
  setInterval(function() {
    count++;
  }, 3000);
  setInterval(function() {
    console.log(count);
  }, 3000);
  count = 50;
}

//Another proof

function foo() {
  var count = 40;
  setInterval(function() {
    count++;
  }, 1000);
  setInterval(function() {
    console.log(count);
  }, 3000);
  count = 50;
}
foo(); 

-----------------------------------------------------
  
var age = 30;
function bar() {
  console.log(age);
}
function foo() {
  var age = 20;
  return bar;
}

var result = foo();
console.log(result()); // 30
console.dir(result);
-----------------------------------------------------
  
var age = 30;

function foo() {
  var age = 20;
  return function bar() {
    console.log(age);
  };
}

var result = foo();
console.log(result()); // 20
console.dir(result);

// =================== XXXXXX ======================= //