From fd1b5cf20630627d138667284d7b6ff101872271 Mon Sep 17 00:00:00 2001
From: Gianluca Guarini <gianluca.guarini@gmail.com>
Date: Fri, 22 Nov 2024 23:09:23 +0100
Subject: [PATCH] updated: avoid adding a template fallback for empty slots

---
 src/generators/template/bindings/slot.js | 20 ++++++++++++--------
 test/generators/template.spec.js         |  9 +++++++++
 2 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/src/generators/template/bindings/slot.js b/src/generators/template/bindings/slot.js
index 063798f..967db68 100644
--- a/src/generators/template/bindings/slot.js
+++ b/src/generators/template/bindings/slot.js
@@ -1,6 +1,7 @@
 import {
   BINDING_ATTRIBUTES_KEY,
   BINDING_NAME_KEY,
+  BINDING_TEMPLATE_KEY,
   BINDING_TYPES,
   BINDING_TYPE_KEY,
   DEFAULT_SLOT_NAME,
@@ -11,6 +12,7 @@ import {
   createBindingAttributes,
   createSelectorProperties,
   createTemplateProperty,
+  getChildrenNodes,
   getName,
   getNodeAttributes,
 } from '../utils.js'
@@ -63,14 +65,16 @@ export default function createSlotBinding(
       ),
     ),
     simplePropertyNode(BINDING_NAME_KEY, builders.literal(slotName)),
-    createTemplateProperty(
-      createNestedBindings(
-        sourceNode,
-        sourceFile,
-        sourceCode,
-        selectorAttribute,
-      ),
-    ),
+    getChildrenNodes(sourceNode).length
+      ? createTemplateProperty(
+          createNestedBindings(
+            sourceNode,
+            sourceFile,
+            sourceCode,
+            selectorAttribute,
+          ),
+        )
+      : simplePropertyNode(BINDING_TEMPLATE_KEY, builders.nullLiteral()),
     ...createSelectorProperties(selectorAttribute),
   ])
 }
diff --git a/test/generators/template.spec.js b/test/generators/template.spec.js
index d3dde74..4083b2c 100644
--- a/test/generators/template.spec.js
+++ b/test/generators/template.spec.js
@@ -1293,6 +1293,15 @@ describe('Generators - Template', () => {
       expect(output[NAME_ATTRIBUTE]).to.be.equal('default')
     })
 
+    it('Slot without fallback', () => {
+      const source = '<slot message={ message } />'
+      const { template } = parse(source)
+      const input = slotBinding(template, 'expr0', FAKE_SRC_FILE, source)
+      const output = evaluateOutput(input)
+
+      expect(output[BINDING_TEMPLATE_KEY]).to.be.not.ok
+    })
+
     it('Slot fallback html', () => {
       const source =
         '<div><slot><ul><li each={item in items}>{item}</li></ul></slot></div>'