Loose mode test, idk if I already had one of these or not

test-app/app/helpers/clock.ts

@@ -0,0 +1,26 @@
+import { cell, resource, resourceFactory } from 'ember-resources';
+
+export function Clock() {
+  let time = cell(new Date());
+
+  return resource(({ on }) => {
+    let interval = setInterval(() => (time.current = new Date()), 1000);
+
+    on.cleanup(() => clearInterval(interval));
+
+    // this works at runtime but TS/Glint can't figure it out
+    // return time;
+
+    // The above is a shorthand for this
+    return () => time.current as Date & { toHTML(): string };
+    // this cast is a Glint Hack
+    // because Glint things Date can't be rendered...
+  });
+}
+
+// template-usage compatibility
+// (if we only invoke fthe resource function from JS, we don't need this)
+resourceFactory(Clock);
+
+// Globals-resolver compatibility
+export default Clock;

test-app/app/helpers/time-format.ts

@@ -0,0 +1,11 @@
+const locale = 'en-US';
+const formatter = new Intl.DateTimeFormat(locale, {
+  hour: 'numeric',
+  minute: 'numeric',
+  second: 'numeric',
+  hour12: false,
+});
+
+export default function timeFormat(input: Date) {
+  return formatter.format(input);
+}

test-app/tests/loose-mode-test.ts

@@ -0,0 +1,39 @@
+import { find, render } from '@ember/test-helpers';
+import { hbs } from 'ember-cli-htmlbars';
+import { module, test } from 'qunit';
+import { setupRenderingTest } from 'ember-qunit';
+
+module('Loose mode', function (hooks) {
+  setupRenderingTest(hooks);
+
+  test('it works', async function (assert) {
+    await render(hbs`
+      {{! template-lint-disable no-curly-component-invocation }}
+      <time>{{ clock }}</time>
+    `);
+
+    assert.dom('time').hasAnyText();
+
+    let initialText = find('time')?.innerText?.trim();
+
+    await new Promise((resolve) => setTimeout(resolve, 1100));
+
+    assert.ok(initialText);
+    assert.notStrictEqual(find('time')?.innerText?.trim(), initialText);
+  });
+
+  test('can be passed to a helper', async function (assert) {
+    await render(hbs`
+      <time>{{time-format (clock) }}</time>
+    `);
+
+    assert.dom('time').hasAnyText();
+
+    let initialText = find('time')?.innerText?.trim();
+
+    await new Promise((resolve) => setTimeout(resolve, 1100));
+
+    assert.ok(initialText);
+    assert.notStrictEqual(find('time')?.innerText?.trim(), initialText);
+  });
+});

test-app/types/glint-registry.d.ts

@@ -2,9 +2,13 @@ import '@glint/environment-ember-loose';
 import '@glint/environment-ember-loose/native-integration';
 
 // import type { ComponentLike, HelperLike, ModifierLike } from "@glint/template";
+import type Clock from 'test-app/helpers/clock';
+import type TimeFormat from 'test-app/helpers/time-format';
 
 declare module '@glint/environment-ember-loose/registry' {
   export default interface Registry {
+    clock: typeof Clock;
+    'time-format': typeof TimeFormat;
     // Examples
     // state: HelperLike<{ Args: {}, Return: State }>;
     // attachShadow: ModifierLike<{ Args: { Positional: [State['update']]}}>;