Merge pull request #11445 from mixonic/helper-bug

[BUGFIX release] Allow recomputation for helpers with arguments

packages/ember-htmlbars/lib/hooks/invoke-helper.js

@@ -1,5 +1,6 @@
 import Ember from 'ember-metal/core'; // Ember.assert
 import { buildHelperStream } from "ember-htmlbars/system/invoke-helper";
+import subscribe from "ember-htmlbars/utils/subscribe";
 
 export default function invokeHelper(morph, env, scope, visitor, params, hash, helper, templates, context) {
 
@@ -16,6 +17,26 @@ export default function invokeHelper(morph, env, scope, visitor, params, hash, h
 
   // Ember.Helper helpers are pure values, thus linkable
   if (helperStream.linkable) {
+
+    if (morph) {
+      // When processing an inline expression the params and hash have already
+      // been linked. Thus, HTMLBars will not link the returned helperStream.
+      // We subscribe the morph to the helperStream here, and also subscribe
+      // the helperStream to any params.
+      let addedDependency = false;
+      for (var i = 0, l = params.length; i < l; i++) {
+        addedDependency = true;
+        helperStream.addDependency(params[i]);
+      }
+      for (var key in hash) {
+        addedDependency = true;
+        helperStream.addDependency(hash[key]);
+      }
+      if (addedDependency) {
+        subscribe(morph, env, scope, helperStream);
+      }
+    }
+
     return { link: true, value: helperStream };
   }
 

packages/ember-htmlbars/tests/helpers/custom_helper_test.js

@@ -85,6 +85,38 @@ QUnit.test('dashed helper can recompute a new value', function() {
   equal(destroyCount, 0, 'destroy is not called on recomputation');
 });
 
+QUnit.test('dashed helper with arg can recompute a new value', function() {
+  var destroyCount = 0;
+  var count = 0;
+  var helper;
+  var HelloWorld = Helper.extend({
+    init() {
+      this._super(...arguments);
+      helper = this;
+    },
+    compute() {
+      return ++count;
+    },
+    destroy() {
+      destroyCount++;
+      this._super();
+    }
+  });
+  registry.register('helper:hello-world', HelloWorld);
+  component = Component.extend({
+    container,
+    layout: compile('{{hello-world "whut"}}')
+  }).create();
+
+  runAppend(component);
+  equal(component.$().text(), '1');
+  run(function() {
+    helper.recompute();
+  });
+  equal(component.$().text(), '2');
+  equal(destroyCount, 0, 'destroy is not called on recomputation');
+});
+
 QUnit.test('dashed shorthand helper is called for param changes', function() {
   var count = 0;
   var HelloWorld = makeHelper(function() {