WIP: Deprecate window global

packages/ember/index.js

@@ -171,7 +171,7 @@ import {
 const Ember = (typeof context.imports.Ember === 'object' && context.imports.Ember) || {};
 
 Ember.isNamespace = true;
-Ember.toString = function () {
+Ember.toString = function() {
   return 'Ember';
 };
 
@@ -457,7 +457,7 @@ Ember.isEqual = isEqual;
 Ember.inject = function inject() {
   assert(
     `Injected properties must be created through helpers, see '${Object.keys(inject)
-      .map((k) => `'inject.${k}'`)
+      .map(k => `'inject.${k}'`)
       .join(' or ')}'`
   );
 };
@@ -647,11 +647,11 @@ Ember.HTMLBars = {
 };
 
 if (ENV.EXTEND_PROTOTYPES.String) {
-  String.prototype.htmlSafe = function () {
+  String.prototype.htmlSafe = function() {
     return htmlSafe(this);
   };
 }
-const deprecateImportFromString = function (
+const deprecateImportFromString = function(
   name,
   message = `Importing ${name} from '@ember/string' is deprecated. Please import ${name} from '@ember/template' instead.`
 ) {
@@ -791,6 +791,36 @@ if (IS_NODE) {
   context.exports.Ember = context.exports.Em = Ember;
 }
 
+if (window) {
+  Object.defineProperty(window, 'Ember', {
+    configurable: true,
+    writable: true,
+    get() {
+      deprecate(
+        "Using window.Ember has been deprecated. Use `import Ember  from 'ember';` instead ",
+        false,
+        {
+          id: 'ember-source.window-global',
+          until: '4.0.0',
+          url: 'tbd',
+          for: 'ember-source',
+          since: { enabled: '3.26.0-beta.1' },
+        }
+      );
+
+      Object.defineProperty(window, 'Ember', {
+        configurable: true,
+        writable: false,
+        get() {
+          return Ember;
+        },
+      });
+
+      return Ember;
+    },
+  });
+}
+
 /**
  @module jquery
  @public