title: Get an error when I call object's properties in Array
body: <p>In typescript code I have an array with objects in it. When I call "getUsers(users)" function, it returns the result as I need, but in console I get this error
  "Uncaught TypeError: Cannot read property 'firstName' of undefined
      at getUsers (index.js:20)
      at index.js:23"</p>
  
  <pre><code>let users = [
  {
      firstName: "John",
      lastName: "Doe",
      age: 34
  },
  {
      firstName: "Jack",
      lastName: "Jackson",
      age: 23
  },
  {
      firstName: "Ann",
      lastName: "Watson",
      age: 24
  }
  ];
  function getUsers(users) {
  for (var i = 0; i &lt;= users.length; i++) {
      console.log(users[i].firstName + " is " + users[i].age + " years old!");
  }
  }
  getUsers(users);
  </code></pre>