Moving Ember.K to legacy addon

config/environment.js

@@ -2,5 +2,9 @@
 'use strict';
 
 module.exports = function(/* environment, appConfig */) {
-  return { };
+  return {
+    EmberENV: {
+      _ENABLE_EMBER_K_SUPPORT: true
+    }
+  };
 };

index.js

@@ -2,5 +2,11 @@
 'use strict';
 
 module.exports = {
-  name: 'ember-2-legacy'
+  name: 'ember-2-legacy',
+
+  included() {
+    this._super.included.apply(this, arguments);
+
+    this.import('vendor/ember-k.js');
+  }
 };

package.json

@@ -36,6 +36,7 @@
     "ember-disable-prototype-extensions": "^1.1.2",
     "ember-export-application-global": "^2.0.0",
     "ember-load-initializers": "^1.0.0",
+    "ember-qunit-assert-helpers": "^0.2.1",
     "ember-resolver": "^4.0.0",
     "ember-source": "~2.17.0",
     "loader.js": "^4.2.3"

tests/unit/ember-k-test.js

@@ -0,0 +1,27 @@
+import Ember from 'ember';
+import { module, test } from 'qunit';
+
+module('Ember.K');
+
+test('that Ember.K is correctly polyfilled', assert => {
+  assert.equal(typeof Ember.K, 'function', 'function is defined on Ember');
+});
+
+test('that Ember.K properly returns this when invoked', function(assert) {
+  let Thing = Ember.Object.extend({
+    randomMethod: Ember.K,
+  });
+
+  let instance = Thing.create();
+  assert.strictEqual(instance.randomMethod(), instance, 'Ember.K returns this');
+});
+
+test('that Ember.K is deprecated', function(assert) {
+  assert.expectDeprecation(() => {
+    let obj = {
+     noop: Ember.K
+    };
+
+    assert.equal(obj, obj.noop());
+  }, 'Ember.K is deprecated in favor of defining a function inline.');
+});

vendor/ember-k.js

@@ -0,0 +1,42 @@
+(function() {
+  var _Ember;
+  if (typeof Ember !== 'undefined') {
+    _Ember = Ember;
+  } else {
+    _Ember = require('ember').default;
+  }
+
+  if (EmberENV && EmberENV._ENABLE_EMBER_K_SUPPORT !== true) {
+    return false;
+  }
+
+  if (_Ember.hasOwnProperty('K')) {
+    return false;
+  }
+
+  /**
+    An empty function useful for some operations. Always returns `this`.
+
+    @method K
+    @return {Object}
+    @public
+    @deprecated
+  */
+  function deprecatedEmberK() { return this; }
+
+  Object.defineProperty(_Ember, 'K', {
+    get() {
+      _Ember.deprecate(
+        'Ember.K is deprecated in favor of defining a function inline.',
+        false,
+        {
+          id: 'ember-metal.ember-k',
+          until: '3.0.0',
+          url: 'https://emberjs.com/deprecations/v2.x#toc_code-ember-k-code'
+        }
+      );
+
+      return deprecatedEmberK;
+    }
+  });
+})();

yarn.lock

@@ -1022,7 +1022,7 @@ broccoli-file-creator@^1.1.1:
     rsvp "~3.0.6"
     symlink-or-copy "^1.0.1"
 
-broccoli-filter@^1.2.2, broccoli-filter@^1.2.3:
+broccoli-filter@^1.0.1, broccoli-filter@^1.2.2, broccoli-filter@^1.2.3:
   version "1.2.4"
   resolved "https://registry.yarnpkg.com/broccoli-filter/-/broccoli-filter-1.2.4.tgz#409afb94b9a3a6da9fac8134e91e205f40cc7330"
   dependencies:
@@ -1756,7 +1756,7 @@ ember-ajax@^3.0.0:
   dependencies:
     ember-cli-babel "^6.0.0"
 
-ember-cli-babel@^6.0.0, ember-cli-babel@^6.0.0-beta.7, ember-cli-babel@^6.3.0, ember-cli-babel@^6.6.0, ember-cli-babel@^6.8.1:
+ember-cli-babel@^6.0.0, ember-cli-babel@^6.0.0-beta.7, ember-cli-babel@^6.3.0, ember-cli-babel@^6.6.0, ember-cli-babel@^6.8.1, ember-cli-babel@^6.9.0:
   version "6.10.0"
   resolved "https://registry.yarnpkg.com/ember-cli-babel/-/ember-cli-babel-6.10.0.tgz#81424acd1d97fb13658168121eeb2007d6edee84"
   dependencies:
@@ -2060,6 +2060,13 @@ ember-load-initializers@^1.0.0:
   dependencies:
     ember-cli-babel "^6.0.0-beta.7"
 
+ember-qunit-assert-helpers@^0.2.1:
+  version "0.2.1"
+  resolved "https://registry.yarnpkg.com/ember-qunit-assert-helpers/-/ember-qunit-assert-helpers-0.2.1.tgz#4a77f8ff252e47cc53db6fa7fb4becb426de8d29"
+  dependencies:
+    broccoli-filter "^1.0.1"
+    ember-cli-babel "^6.9.0"
+
 ember-qunit@^3.1.0:
   version "3.1.0"
   resolved "https://registry.yarnpkg.com/ember-qunit/-/ember-qunit-3.1.0.tgz#4995a6207ab66b5d0cf807d0459d48f55f9eee5f"