Class sugar

README.md

Class sugar

This project is a reference corpus for exploring similarities and differences in conventional JavaScript inheritance ("Naive"), ES6 Classes ("Classes"), as well as an example of trying to ape classes ("Sugarfree"). It consists of a chart of JavaScript property descriptors where comparison is possible, and of reference implementations of class-like structures/systems, in:

• ES6 classes
• naive construction usage
• naive prototype extending via Object.create
• Sugarfree "ES6 emulation-mode"
• ES6 extend which PropertyDescriptor wise looks identical to ES6 Classes

	writable	enumerable	configurable	value	diff from default if prop
Things we can do something about
Default defineProperty {value}	false	false	false	value
Naive.prototype.bing	false	false	false	[Function: bing]
Classes.prototype.bing	true	false	true	[Function: bing]	{enumerable:true,value}
Classes.singleton	true	false	true	[Function: singleton]	{enumerable:true,configurable:true,value}
Language behavior
Classes.prototype	false	false	false	Classes{}
Naive.prototype	true	false	false	{}
NaiveExtend.prototype	true	false	false	NaiveExtend {constructor: NaiveExtend}
Classes.protype.constructor	false[1]	false	true	[Function: Classes]
Naive.prototype.constructor	true	false	true	[Function]
NaiveExtend.prototype.constructor	true	true	true	[Function: NaiveExtend]

[1] node v5.10 does not reflect this setting

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Reference

This is possible and provoked by seeing, and the desire to get a quick/fast code reference for it.

Preview of next release of “Exploring ES6” (@exploringjs): the attributes of properties created by classes. — Axel Rauschmayer, https://twitter.com/rauschma/status/718868475100413953

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Help

I am seeking ways to recreate objects with closer parity (in the language behaviors section) to Classes, without using ES6 Classes.

classes-extend.js

let Classes= require("./classes")
class ClassesExtend extends Classes{
  moar(){ return "boost" }
}
module.exports= ClassesExtend

classes.js

let _singleton
class Classes {
  bing(){ return "bang" }
  static singleton() { return _singleton || (_singleton = new Classes()) }
}
module.exports= Classes

index.js

let Classes= require("./classes"), Naive= require("./naive"), NaiveExtend= require("./NaiveExtend")
Object.getOwnPropertyDescriptor(Naive, "singleton")
Object.getOwnPropertyDescriptor(classes.prototype, "bing")
Object.getOwnPropertyDescriptor(classes, "singleton")

Object.getOwnPropertyDescriptor(Classes, "prototype")
Object.getOwnPropertyDescriptor(Naive, "prototype")
Object.getOwnPropertyDescriptor(NaiveExtend, "prototype")
Object.getOwnPropertyDescriptor(Classes.prototype, "constructor")
Object.getOwnPropertyDescriptor(Naive.prototype, "constructor")
Object.getOwnPropertyDescriptor(NaiveExtend.prototype, "constructor")

naive-extend.js

let Naive= require("./naive")
function NaiveExtend(){
  Naive.call(this)
}
let moar= {value: function(){return "boost"}}
NaiveExtend.prototype= Object.create(Naive.prototype, {moar})
NaiveExtend.prorotype.constructor= NiaveExtend
module.exports= NaiveExtend

naive.js

let _singleton
function Naive(){}
Object.defineProperties(Naive.prototype, {
  bing: {
    value: function(){ return "bang" }
}})
Object.defineProperties(Naive, {
  singleton: {
    value: function() { return _singleton || (_singleton = new Naive()) }
}})
module.exports= Naive

sugarfree.js

let _singleton
function Sugarfree(){}
Object.defineProperties(Sugarfree.prototype, {
  bing: {
    value: function(){ return "bang" },
    writable: true,
    enumerable: false,
    configurable: true
}})
Object.defineProperties(Sugarfree, {
  singleton: {
    value: function() { return _singleton || (_singleton = new Sugarfree()) },
    writable: true,
    enumerable: false,
    configurable: true
}})
module.exports= Sugarfree