IIFE (Immediately Invoked Function Expression)

What pattern does this code demonstrate?

var module = (function() {
  var privateVar = 'I am private';
  
  function privateMethod() {
    return privateVar;
  }
  
  return {
    publicMethod: function() {
      return privateMethod();
    }
  };
})();

Factory pattern
Singleton pattern
Prototype pattern
Module pattern
This code demonstrates the Module pattern. The Module pattern uses an IIFE to create a closure with private variables and methods. It then returns an object with public methods that can access the private members. In this example, 'privateVar' and 'privateMethod' are only accessible within the IIFE, while 'publicMethod' is exposed through the returned object. This pattern was widely used before ES6 modules to create encapsulated code units with public APIs and private implementation details. The Module pattern brings the concept of public and private access modifiers to JavaScript, allowing developers to hide complex implementation details and expose a clean, simple interface for other code to interact with.

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