[BUGFIX release] Only freeze params, hash when WeakMap available

packages/ember-glimmer/lib/utils/references.js

@@ -1,4 +1,8 @@
-import { symbol, EmptyObject } from 'ember-utils';
+import {
+  HAS_NATIVE_WEAKMAP,
+  symbol,
+  EmptyObject
+} from 'ember-utils';
 import {
   get,
   set,
@@ -289,8 +293,10 @@ export class SimpleHelperReference extends CachedReference {
       let namedValue = named.value();
 
       runInDebug(() => {
-        Object.freeze(positionalValue);
-        Object.freeze(namedValue);
+        if (HAS_NATIVE_WEAKMAP) {
+          Object.freeze(positionalValue);
+          Object.freeze(namedValue);
+        }
       });
 
       let result = helper(positionalValue, namedValue);
@@ -324,8 +330,10 @@ export class SimpleHelperReference extends CachedReference {
     let namedValue = named.value();
 
     runInDebug(() => {
-      Object.freeze(positionalValue);
-      Object.freeze(namedValue);
+      if (HAS_NATIVE_WEAKMAP) {
+        Object.freeze(positionalValue);
+        Object.freeze(namedValue);
+      }
     });
 
     return helper(positionalValue, namedValue);
@@ -354,8 +362,10 @@ export class ClassBasedHelperReference extends CachedReference {
     let namedValue = named.value();
 
     runInDebug(() => {
-      Object.freeze(positionalValue);
-      Object.freeze(namedValue);
+      if (HAS_NATIVE_WEAKMAP) {
+        Object.freeze(positionalValue);
+        Object.freeze(namedValue);
+      }
     });
 
     return instance.compute(positionalValue, namedValue);

packages/ember-glimmer/tests/integration/helpers/custom-helper-test.js

@@ -3,6 +3,7 @@ import { RenderingTest, moduleFor } from '../../utils/test-case';
 import { makeBoundHelper } from '../../utils/helpers';
 import { runDestroy } from 'internal-test-helpers';
 import { set } from 'ember-metal';
+import { HAS_NATIVE_WEAKMAP } from 'ember-utils';
 
 let assert = QUnit.assert;
 
@@ -174,6 +175,30 @@ moduleFor('Helpers test: custom helpers', class extends RenderingTest {
     assert.strictEqual(destroyCount, 0, 'destroy is not called on recomputation');
   }
 
+  ['@test helper params can be returned']() {
+    this.registerHelper('hello-world', values => {
+      return values;
+    });
+
+    this.render('{{#each (hello-world model) as |item|}}({{item}}){{/each}}', {
+      model: ['bob']
+    });
+
+    this.assertText('(bob)');
+  }
+
+  ['@test helper hash can be returned']() {
+    this.registerHelper('hello-world', (_, hash) => {
+      return hash.model;
+    });
+
+    this.render(`{{get (hello-world model=model) 'name'}}`, {
+      model: { name: 'bob' }
+    });
+
+    this.assertText('bob');
+  }
+
   ['@test simple helper is called for param changes']() {
     let computeCount = 0;
 
@@ -602,7 +627,7 @@ let addingPropertyToFrozenObjectThrows = (() => {
   }
 })();
 
-if (!EmberDev.runningProdBuild && (
+if (!EmberDev.runningProdBuild && HAS_NATIVE_WEAKMAP && (
   pushingIntoFrozenArrayThrows ||
     assigningExistingFrozenPropertyThrows ||
     addingPropertyToFrozenObjectThrows

packages/ember-metal/lib/meta.js

@@ -2,7 +2,12 @@
 // Remove "use strict"; from transpiled module until
 // https://bugs.webkit.org/show_bug.cgi?id=138038 is fixed
 
-import { EmptyObject, lookupDescriptor, symbol } from 'ember-utils';
+import {
+  HAS_NATIVE_WEAKMAP,
+  EmptyObject,
+  lookupDescriptor,
+  symbol
+} from 'ember-utils';
 import isEnabled from './features';
 import { protoMethods as listenerMethods } from './meta_listeners';
 import { runInDebug, assert } from './debug';
@@ -460,17 +465,6 @@ if (isEnabled('mandatory-setter')) {
   };
 }
 
-const HAS_NATIVE_WEAKMAP = (function() {
-  // detect if `WeakMap` is even present
-  let hasWeakMap = typeof WeakMap === 'function';
-  if (!hasWeakMap) { return false; }
-
-  let instance = new WeakMap();
-  // use `Object`'s `.toString` directly to prevent us from detecting
-  // polyfills as native weakmaps
-  return Object.prototype.toString.call(instance) === '[object WeakMap]';
-})();
-
 let setMeta, peekMeta;
 
 // choose the one appropriate for given platform

packages/ember-utils/lib/index.js

@@ -30,3 +30,4 @@ export { default as makeArray } from './make-array';
 export { default as applyStr } from './apply-str';
 export { default as NAME_KEY } from './name';
 export { default as toString } from './to-string';
+export { HAS_NATIVE_WEAKMAP } from './weak-map-utils';

packages/ember-utils/lib/weak-map-utils.js

@@ -0,0 +1,10 @@
+export const HAS_NATIVE_WEAKMAP = (function() {
+  // detect if `WeakMap` is even present
+  let hasWeakMap = typeof WeakMap === 'function';
+  if (!hasWeakMap) { return false; }
+
+  let instance = new WeakMap();
+  // use `Object`'s `.toString` directly to prevent us from detecting
+  // polyfills as native weakmaps
+  return Object.prototype.toString.call(instance) === '[object WeakMap]';
+})();