From b7cea9820f025b42df6a0fcfd95020267a7c8d36 Mon Sep 17 00:00:00 2001
From: Douglas Wade <douglas.b.wade@gmail.com>
Date: Sun, 31 Dec 2023 15:50:00 -0800
Subject: [PATCH 1/2] feat(NOBUG): multiple interpolations in a single
 attribute triggers warning

---
 packages/core/src/api/render.ts      | 13 +++++++++++--
 packages/core/tst/api/render.test.ts | 13 ++++++++++++-
 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/packages/core/src/api/render.ts b/packages/core/src/api/render.ts
index ffea1f15..39c9d623 100644
--- a/packages/core/src/api/render.ts
+++ b/packages/core/src/api/render.ts
@@ -47,7 +47,9 @@ const renderToString = (
             const placeholder = uuid();
 
             let suffix = '';
-            if (!strings[i + 1].startsWith('"')) {
+            if (!strings[i + 1].includes('"')) {
+                throw new Error('Tybalt currently only supports one reactive per attribute. Please consolidate.');
+            } else if (!strings[i + 1].startsWith('"')) {
                 suffix = strings[i + 1].split('"')[0];
             }
 
@@ -85,13 +87,20 @@ const renderToString = (
         if (Array.isArray(key)) {
             const children = key.map((key: HtmlTemplate) => renderToString(key, eventPlaceholders, setAttributePlaceholders)).join('');
             return `${prev}${curr}${children}`;
-        } 
+        }
 
         if (key?.addListener) {
             if (key?.value.strings && key?.value.keys) {
                 return `${prev}${curr}${renderToString(key, eventPlaceholders, setAttributePlaceholders)}`;
             }
 
+            if (Array.isArray(key.value)) {
+                const children = key
+                    .value
+                    .map((templ: HtmlTemplate) => renderToString(templ, eventPlaceholders, setAttributePlaceholders)).join('');
+                return `${prev}${curr}${children}`;
+            } 
+
             return `${prev}${curr}${key.value}`;
         }
         
diff --git a/packages/core/tst/api/render.test.ts b/packages/core/tst/api/render.test.ts
index 32fc5d10..3696b4f2 100644
--- a/packages/core/tst/api/render.test.ts
+++ b/packages/core/tst/api/render.test.ts
@@ -105,5 +105,16 @@ describe('render', () => {
         const wrapper = render(template)[0];
 
         expect(wrapper.outerHTML).toBe(`<a class="my-class" href="${attributeValue.value}"></a>`);
-    })
+    });
+
+    it('should not support multiple interpolations in a single attribute', () => {
+        const firstAttributeValue = reactive('bar');
+        const secondAttributeValue = reactive('baz');
+
+        const template = html`<div class="foo ${firstAttributeValue} ${secondAttributeValue}"></div>`;
+
+        expect(() => {
+            render(template)
+        }).toThrow('Tybalt currently only supports one reactive per attribute. Please consolidate.')
+    });
 });
\ No newline at end of file

From 71d8c39e5c73b28967e4e642c670d5da753ae11e Mon Sep 17 00:00:00 2001
From: Douglas Wade <douglas.b.wade@gmail.com>
Date: Sun, 31 Dec 2023 16:10:21 -0800
Subject: [PATCH 2/2] chore(NOBUG): Increase code coverage

---
 packages/core/tst/api/render.test.ts | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/packages/core/tst/api/render.test.ts b/packages/core/tst/api/render.test.ts
index 3696b4f2..4b4827af 100644
--- a/packages/core/tst/api/render.test.ts
+++ b/packages/core/tst/api/render.test.ts
@@ -117,4 +117,16 @@ describe('render', () => {
             render(template)
         }).toThrow('Tybalt currently only supports one reactive per attribute. Please consolidate.')
     });
-});
\ No newline at end of file
+    
+    it('should emit a warning if a placeholder is unexpectedly not found', () => {
+        const listener = jest.fn();
+        const template = html`<button type="button" @click="${listener}"></button>`;
+
+        jest.spyOn(Element.prototype, 'querySelector').mockImplementation(() => null);
+        const warnSpy = jest.spyOn(console, 'warn').mockImplementation(() => '');
+        render(template)[0];
+
+        expect(warnSpy).toHaveBeenCalledTimes(1);
+        expect(warnSpy.mock.calls[0][0].startsWith('expected to find element with selector ')).toBeTruthy();
+    });
+});