Object.define ==> Object.mixin??

Rick Waldron waldron.rick at gmail.com
Tue Dec 11 10:00:49 PST 2012

On Tue, Dec 11, 2012 at 12:28 PM, Allen Wirfs-Brock
<allen at wirfs-brock.com>wrote:

> I'm the past we discussed issues surrounding the semantic differences
> between "put" and "define" and we've agreed to include Object.assign in
> ES6.  We have also discussed Object.define but have not yet made a decision
> to include it.
> Nicholas Zaka recently posted a short article that addresses issues
> relating to the assign/define distinction
> http://www.nczonline.net/blog/2012/12/11/are-your-mixins-ecmascript-5-compatible/
> as they already surface in ES5.
> For me, this article reenforces that we really need to have something like
> Object.define in ES6.
> It also made me think that perhaps Object.mixin might be a more intuitive
> name for such a function.

This name is certainly more real-word-friendly.

The example code that follows "A pure ECMAScript 5 version of mixin() would
be:" is basically what I imagined Object.define would be, but with a slight
modification in that Object.assign returns the target object, so should

Object.mixin = function(receiver, supplier) {
  return Object.keys(supplier).reduce(function(receiver, property) {
    return Object.defineProperty(
      receiver, property, Object.getOwnPropertyDescriptor(supplier,
  }, receiver);

var a = {}, name = "Rick";

var b = Object.mixin(a, {
  get name() {
    return name;

console.log( a.name ); // "Rick"
console.log( b.name ); // "Rick"
console.log( a === b ); // true

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