Exporting variables and functions in modules via closures in JavaScript

Sometimes you need to make certain variables and functions of a module accessible from the outside. Let's see how it's done. Let's say we have the following module:

javascript;(function() {
  let str = 'a module variable';
  
  function func() {
    alert('a module function');
  }
})();

Let's export our function func. To do this, we write it into the property of the window object embedded in the browser:

javascript;(function() {
  let str = 'a module variable';
  
  function func() {
    alert('a module function');
  }
  
  window.func = func;
})();

Now we can call our function from outside the module:

javascript;(function() {
  let str = 'a module variable';
  
  function func() {
    alert('a module function');
  }
  
  window.func = func;
})();

window.func(); // shows 'a module function'

In this case, it is not necessary to call the function as a property of the window object:

javascript;(function() {
  let str = 'a module variable';
  
  function func() {
    alert('a module function');
  }
  
  window.func = func;
})();

func(); // shows 'a module function'

javascript;(function() {
  let str1 = 'a module variable';
  let str2 = 'a module variable';
  let str3 = 'a module variable';
  
  function func1() {
    alert('a module function');
  }
  function func2() {
    alert('a module function');
  }
  function func3() {
    alert('a module function');
  }
})();