Ecmascript6 - let examples

let.js

(function(){
  "use strict"

  var case1 = function(){
    console.log("foo", foo);
    if(true){
      var foo = 'foo';
      console.log("foo", foo);
    }
    console.log("foo", foo);
  };

  var case2 = function(){
    console.log("bar", bar);

    if(true){
      let bar = 'bar';
      console.log("bar", bar);
    }

    console.log("bar", bar);
  };

  var case3 = function(){
    for (var i = 0; i < 10; i++) {
      var btn = document.createElement('button');
      btn.textContent = "Element with number " + i;
      btn.addEventListener('click', function(){
        console.log("button number is:", i);
      })

      document.body.appendChild(btn);
      document.body.appendChild(document.createElement('br'));

    };
  };

  var case4 = function(){
    for (var i = 0; i < 10; i++) {
      var btn = document.createElement('button');
      btn.textContent = "Another element with number " + i;
      let j = i;
      btn.addEventListener('click', function(){
        console.log("button number is:", j);
      })

      document.body.appendChild(btn);
      document.body.appendChild(document.createElement('br'));

    };
  };

  case1();
  //Remember that case2() cause a error and prevent parsing rest of script
  //case2();
  case3();
  case4();

})()