Inheritance in JS

inherit.js

/*\
 *  Sometimes I'm amused by how versatile and expressive JavaScript
 *  can be when it comes to even the smallest of details at its core;
 *  like declaring inheritance patterns.
 *  [Or global variable declaration.](http://goo.gl/iqk1J)
 *  
 *  We are here to talk about the former, because other times it's a
 *  baffling experience to choose the right way.
 *  
 *  I've listed 5 ways of performing roughly the same task below.
 *  In the comments, tell me why/when you would or wouldn't use a
 *  particular one, and which one is your syntax of choice, and of
 *  course, why.
 *  
 *  Also, if you know about a method different from my listings, let
 *  me know and I'll add it!
 *  
 *  tl;dr
 *  Inheritance in JS. How? Why that way?
\*/

// This is how each is used:
var foo = new Foo()
foo.bar() // returns 'OK' if proper


// #1
var Foo = function() {
  this.bar = function() {
    return 'OK'
  }
}

// #2
var Foo = function() {
  var out = function() {}
  out.bar = function() {
    return 'OK'
  }
  return out
}

// #3
var Foo = function() {
  var out = {}
  out.bar = function() {
    return 'OK'
  }
  return out
}

// #4
var Foo = (function() {
  var Foo = function() {}
  Foo.prototype.bar = function() {
    return 'OK'
  }
})()

// #5
var Foo = function() {}
Foo.prototype = (function() {
  return {bar: bar}
  function bar () {
    return 'OK'
  }
})()