From 2003e14a957d783e1a308765082b8d269c08b16c Mon Sep 17 00:00:00 2001
From: Sage Abdullah <sage.abdullah@torchbox.com>
Date: Thu, 7 Mar 2024 14:52:28 +0000
Subject: [PATCH] Allow TeleportController to have any number of child nodes of
 any kind

---
 .../controllers/TeleportController.test.js    | 98 ++++++++++++++++---
 client/src/controllers/TeleportController.ts  | 20 ++--
 2 files changed, 93 insertions(+), 25 deletions(-)

diff --git a/client/src/controllers/TeleportController.test.js b/client/src/controllers/TeleportController.test.js
index 0c0700da7414..3daf4a8f4984 100644
--- a/client/src/controllers/TeleportController.test.js
+++ b/client/src/controllers/TeleportController.test.js
@@ -89,9 +89,9 @@ describe('TeleportController', () => {
 
       await Promise.resolve();
 
-      expect(document.getElementById('target-container').innerHTML).toEqual(
-        '<div id="content">Some content</div>',
-      );
+      expect(
+        document.getElementById('target-container').innerHTML.trim(),
+      ).toEqual('<div id="content">Some content</div>');
     });
 
     it('should allow for a default target container within the root element of a shadow DOM', async () => {
@@ -136,9 +136,9 @@ describe('TeleportController', () => {
 
       await Promise.resolve();
 
-      expect(document.getElementById('target-container').innerHTML).toEqual(
-        '<div id="content">Some content</div>',
-      );
+      expect(
+        document.getElementById('target-container').innerHTML.trim(),
+      ).toEqual('<div id="content">Some content</div>');
     });
 
     it('should not clear the target container if the reset value is unset (false)', async () => {
@@ -160,12 +160,84 @@ describe('TeleportController', () => {
 
       await Promise.resolve();
 
+      const contents = document.getElementById('target-container').innerHTML;
+      expect(contents).toContain('<p>I should still be here</p>');
+      expect(contents).toContain('<div id="content">Some content</div>');
+    });
+
+    it('should allow the template to contain multiple children', async () => {
+      document.body.innerHTML += `
+        <div id="target-container"></div>
+        `;
+
+      const template = document.querySelector('template');
+      template.setAttribute(
+        'data-w-teleport-target-value',
+        '#target-container',
+      );
+
+      const otherTemplateContent = document.createElement('div');
+      otherTemplateContent.innerHTML = 'Other content';
+      otherTemplateContent.id = 'other-content';
+      template.content.appendChild(otherTemplateContent);
+
+      expect(document.getElementById('target-container').innerHTML).toEqual('');
+
+      application.start();
+
+      await Promise.resolve();
+
+      const container = document.getElementById('target-container');
+      const content = container.querySelector('#content');
+      const otherContent = container.querySelector('#other-content');
+      expect(content).not.toBeNull();
+      expect(otherContent).not.toBeNull();
+      expect(content.innerHTML.trim()).toEqual('Some content');
+      expect(otherContent.innerHTML.trim()).toEqual('Other content');
+    });
+
+    it('should not throw an error if the template content is empty', async () => {
+      document.body.innerHTML += `
+        <div id="target-container"><p>I should still be here</p></div>
+        `;
+
+      const template = document.querySelector('template');
+      template.setAttribute(
+        'data-w-teleport-target-value',
+        '#target-container',
+      );
+
+      expect(document.getElementById('target-container').innerHTML).toEqual(
+        '<p>I should still be here</p>',
+      );
+
+      const errors = [];
+
+      document.getElementById('template').innerHTML = '';
+      application.handleError = (error, message) => {
+        errors.push({ error, message });
+      };
+
+      await Promise.resolve(application.start());
+
+      expect(errors).toEqual([]);
+
       expect(document.getElementById('target-container').innerHTML).toEqual(
-        '<p>I should still be here</p><div id="content">Some content</div>',
+        '<p>I should still be here</p>',
       );
     });
 
-    it('should throw an error if the template content is empty', async () => {
+    it('should allow erasing the target container by using an empty template with reset value set to true', async () => {
+      document.body.innerHTML += `
+        <div id="target-container"><p>I should not be here</p></div>
+        `;
+
+      const template = document.querySelector('template');
+      template.setAttribute(
+        'data-w-teleport-target-value',
+        '#target-container',
+      );
+      template.setAttribute('data-w-teleport-reset-value', 'true');
       const errors = [];
 
       document.getElementById('template').innerHTML = '';
@@ -176,12 +248,10 @@ describe('TeleportController', () => {
 
       await Promise.resolve(application.start());
 
-      expect(errors).toEqual([
-        {
-          error: new Error('Invalid template content.'),
-          message: 'Error connecting controller',
-        },
-      ]);
+      expect(errors).toEqual([]);
+
+      const contents = document.getElementById('target-container').innerHTML;
+      expect(contents).toEqual('');
     });
 
     it('should throw an error if a valid target container cannot be resolved', async () => {
diff --git a/client/src/controllers/TeleportController.ts b/client/src/controllers/TeleportController.ts
index ff9d12602540..3c1221f239cd 100644
--- a/client/src/controllers/TeleportController.ts
+++ b/client/src/controllers/TeleportController.ts
@@ -46,7 +46,7 @@ export class TeleportController extends Controller<HTMLTemplateElement> {
     const complete = () => {
       if (completed) return;
       if (this.resetValue) target.innerHTML = '';
-      target.append(this.templateElement);
+      target.append(...this.templateFragment.childNodes);
       this.dispatch('appended', { cancelable: false, detail: { target } });
       completed = true;
       if (this.keepValue) return;
@@ -88,22 +88,20 @@ export class TeleportController extends Controller<HTMLTemplateElement> {
   }
 
   /**
-   * Resolve a valid HTMLElement from the controlled element's children.
+   * Returns a fresh copy of the DocumentFragment from the controlled element.
    */
-  get templateElement() {
-    const templateElement =
-      this.element.content.firstElementChild?.cloneNode(true);
-
-    if (!(templateElement instanceof HTMLElement)) {
-      throw new Error('Invalid template content.');
-    }
+  get templateFragment() {
+    const content = this.element.content;
+    // https://developer.mozilla.org/en-US/docs/Web/API/Node/cloneNode (returns the same type)
+    // https://github.com/microsoft/TypeScript/issues/283 (TypeScript will return as Node, incorrectly)
+    const templateFragment = content.cloneNode(true) as typeof content;
 
     // HACK:
     // cloneNode doesn't run scripts, so we need to create new script elements
     // and copy the attributes and innerHTML over. This is necessary when we're
     // teleporting a template that contains legacy init code, e.g. initDateChooser.
     // Only do this for inline scripts, as that's what we're expecting.
-    templateElement
+    templateFragment
       .querySelectorAll('script:not([src], [type])')
       .forEach((script) => {
         const newScript = document.createElement('script');
@@ -114,6 +112,6 @@ export class TeleportController extends Controller<HTMLTemplateElement> {
         script.replaceWith(newScript);
       });
 
-    return templateElement;
+    return templateFragment;
   }
 }