ES3 Implementation

IE6 compatible. Just for fun. Nothing serious. Tell me what you think about this 😄

function Mixin1 (superClass) {
  function Mixin1 () {
    // Passing constructor arguments
    superClass.apply(this, arguments)
  }
  Mixin1.prototype = new superClass()
  // Calling super class method
  Mixin1.prototype.callSuperClassMethodExample = function () {
    superClass.prototype.superClassMethod()
    return this
  }
  return Mixin1
}

function Mixin2 (superClass) {
  function Mixin2 () {
    superClass.apply(this, arguments)
  }
  Mixin2.prototype = new superClass()
  Mixin2.prototype.anotherMixinMethod = function () {
    alert('Hello from mixin!')
  }
  return Mixin2
}

// Composing mixins
function Mixin3 (superClass) {
  return Mixin2(Mixin1(superClass))
}

// Test it
var Foo = (function () {
  function Foo () {
  }
  Foo.prototype.superClassMethod = function () {
    alert('Hello from superClass!')
  }
  return Mixin3(Foo)
}())

new Foo().callSuperClassMethodExample().anotherMixinMethod()

[trusktr]

Mixin1.prototype = new superClass()

I don’t think you should use new there, since that might run logic meant for the instance when the instance is created, not when the class is defined. I think you can use Object.create (polyfill), if that works in ES3?

Mixin1.prototype = Object.create(superClass.prototype)

[trusktr]

superClass.apply(this, arguments); // Transfer statics.

Oh yep, forgot about those. I think you meant Object.assign(IcedFrisbyNock, superClass);, but yeah, good point, ES6 classes do that automatically too.