[BUGFIX beta] Allow boolean values for current-when

As the docs say, `A link will be active if current-when is true`.
Looks like this might have been broken since 1.13 and emberjs#12344
did not seem to actually fix this particular bug.

Related issues:

- emberjs#12512
- emberjs#12630 (fix was not merged)
- emberjs#12296

packages/ember-glimmer/lib/components/link-to.js

@@ -552,8 +552,12 @@ const LinkComponent = EmberComponent.extend({
     let routing = get(this, '_routing');
     let models = get(this, 'models');
     let resolvedQueryParams = get(this, 'resolvedQueryParams');
-
     let currentWhen = get(this, 'current-when');
+
+    if (typeof currentWhen === 'boolean') {
+      return currentWhen ? get(this, 'activeClass') : false;
+    }
+
     let isCurrentWhenSpecified = !!currentWhen;
     currentWhen = currentWhen || get(this, 'qualifiedRouteName');
     currentWhen = currentWhen.split(' ');

packages/ember/tests/helpers/link_to_test.js

@@ -576,6 +576,25 @@ QUnit.test('The {{link-to}} helper supports multiple current-when routes', funct
   equal(jQuery('#link3.active', '#qunit-fixture').length, 0, 'The link is not active since current-when does not contain the active route');
 });
 
+QUnit.test('The {{link-to}} helper supports boolean values for current-when', function() {
+  Router.map(function(match) {
+    this.route('index', { path: '/' }, function() {
+      this.route('about');
+    });
+
+    this.route('item');
+  });
+
+  setTemplate('index', compile('<h3>Home</h3>{{outlet}}'));
+  setTemplate('index/about', compile("{{#link-to 'item' id='other-link' current-when=true}}ITEM{{/link-to}}"));
+
+  bootApplication();
+
+  run(() => router.handleURL('/about'));
+
+  equal(jQuery('#other-link.active', '#qunit-fixture').length, 1, 'The link is active since current-when is true');
+});
+
 QUnit.test('The {{link-to}} helper defaults to bubbling', function() {
   setTemplate('about', compile("<div {{action 'hide'}}>{{#link-to 'about.contact' id='about-contact'}}About{{/link-to}}</div>{{outlet}}"));
   setTemplate('about/contact', compile("<h1 id='contact'>Contact</h1>"));