fix(renderer): fix missing slot ref callback handling

src/declarations/stencil-private.ts

@@ -1331,6 +1331,12 @@ export interface RenderNode extends HostElement {
    */
   host?: Element;
 
+  /**
+   * On Ref Function:
+   * Callback function to be called when the slotted node ref is ready.
+   */
+  ['s-rf']?: (elm: Element) => unknown;
+
   /**
    * Is initially hidden
    * Whether this node was originally rendered with the `hidden` attribute.

src/runtime/dom-extras.ts

@@ -47,6 +47,7 @@ export const patchCloneNode = (HostElementPrototype: HTMLElement) => {
         's-ol',
         's-nr',
         's-si',
+        's-rf',
       ];
 
       for (; i < srcNode.childNodes.length; i++) {

src/runtime/vdom/vdom-render.ts

@@ -149,6 +149,9 @@ const createElm = (oldParentVNode: d.VNode, newParentVNode: d.VNode, childIndex:
       // remember the slot name, or empty string for default slot
       elm['s-sn'] = newVNode.$name$ || '';
 
+      // remember the ref callback function
+      elm['s-rf'] = newVNode.$attrs$?.ref;
+
       // check if we've got an old vnode for this slot
       oldVNode = oldParentVNode && oldParentVNode.$children$ && oldParentVNode.$children$[childIndex];
       if (oldVNode && oldVNode.$tag$ === newVNode.$tag$ && oldParentVNode.$elm$) {
@@ -1094,6 +1097,8 @@ render() {
               }
             }
           }
+
+          nodeToRelocate && typeof slotRefNode['s-rf'] === 'function' && slotRefNode['s-rf'](nodeToRelocate);
         } else {
           // this node doesn't have a slot home to go to, so let's hide it
           if (nodeToRelocate.nodeType === NODE_TYPE.ElementNode) {

test/karma/test-app/components.d.ts

@@ -369,6 +369,8 @@ export namespace Components {
     interface SlotParentTagChangeRoot {
         "element": string;
     }
+    interface SlotRef {
+    }
     interface SlotReorder {
         "reordered": boolean;
     }
@@ -1373,6 +1375,12 @@ declare global {
         prototype: HTMLSlotParentTagChangeRootElement;
         new (): HTMLSlotParentTagChangeRootElement;
     };
+    interface HTMLSlotRefElement extends Components.SlotRef, HTMLStencilElement {
+    }
+    var HTMLSlotRefElement: {
+        prototype: HTMLSlotRefElement;
+        new (): HTMLSlotRefElement;
+    };
     interface HTMLSlotReorderElement extends Components.SlotReorder, HTMLStencilElement {
     }
     var HTMLSlotReorderElement: {
@@ -1622,6 +1630,7 @@ declare global {
         "slot-no-default": HTMLSlotNoDefaultElement;
         "slot-parent-tag-change": HTMLSlotParentTagChangeElement;
         "slot-parent-tag-change-root": HTMLSlotParentTagChangeRootElement;
+        "slot-ref": HTMLSlotRefElement;
         "slot-reorder": HTMLSlotReorderElement;
         "slot-reorder-root": HTMLSlotReorderRootElement;
         "slot-replace-wrapper": HTMLSlotReplaceWrapperElement;
@@ -2008,6 +2017,8 @@ declare namespace LocalJSX {
     interface SlotParentTagChangeRoot {
         "element"?: string;
     }
+    interface SlotRef {
+    }
     interface SlotReorder {
         "reordered"?: boolean;
     }
@@ -2187,6 +2198,7 @@ declare namespace LocalJSX {
         "slot-no-default": SlotNoDefault;
         "slot-parent-tag-change": SlotParentTagChange;
         "slot-parent-tag-change-root": SlotParentTagChangeRoot;
+        "slot-ref": SlotRef;
         "slot-reorder": SlotReorder;
         "slot-reorder-root": SlotReorderRoot;
         "slot-replace-wrapper": SlotReplaceWrapper;
@@ -2351,6 +2363,7 @@ declare module "@stencil/core" {
             "slot-no-default": LocalJSX.SlotNoDefault & JSXBase.HTMLAttributes<HTMLSlotNoDefaultElement>;
             "slot-parent-tag-change": LocalJSX.SlotParentTagChange & JSXBase.HTMLAttributes<HTMLSlotParentTagChangeElement>;
             "slot-parent-tag-change-root": LocalJSX.SlotParentTagChangeRoot & JSXBase.HTMLAttributes<HTMLSlotParentTagChangeRootElement>;
+            "slot-ref": LocalJSX.SlotRef & JSXBase.HTMLAttributes<HTMLSlotRefElement>;
             "slot-reorder": LocalJSX.SlotReorder & JSXBase.HTMLAttributes<HTMLSlotReorderElement>;
             "slot-reorder-root": LocalJSX.SlotReorderRoot & JSXBase.HTMLAttributes<HTMLSlotReorderRootElement>;
             "slot-replace-wrapper": LocalJSX.SlotReplaceWrapper & JSXBase.HTMLAttributes<HTMLSlotReplaceWrapperElement>;

test/karma/test-app/slot-ref/cmp.tsx

@@ -0,0 +1,24 @@
+import { Component, Element, h, Host } from '@stencil/core';
+
+@Component({
+  tag: 'slot-ref',
+  shadow: false,
+  scoped: true,
+})
+export class SlotRef {
+  @Element() hostElement: HTMLElement;
+
+  render() {
+    return (
+      <Host>
+        <slot
+          name="title"
+          ref={(el) => {
+            this.hostElement.setAttribute('data-ref-id', el.id);
+            this.hostElement.setAttribute('data-ref-tagname', el.tagName);
+          }}
+        />
+      </Host>
+    );
+  }
+}

test/karma/test-app/slot-ref/index.html

@@ -0,0 +1,6 @@
+<!DOCTYPE html>
+<meta charset="utf8">
+<script src="./build/testapp.esm.js" type="module"></script>
+<script src="./build/testapp.js" nomodule></script>
+
+<slot-ref><span slot="title" id="slotted-element-id">Hello World!</span></slot-ref>

test/karma/test-app/slot-ref/karma.spec.ts

@@ -0,0 +1,19 @@
+import { setupDomTests, waitForChanges } from '../util';
+
+describe('slot-ref', function () {
+  const { setupDom, tearDownDom } = setupDomTests(document);
+  let app: HTMLElement;
+
+  beforeEach(async () => {
+    app = await setupDom('/slot-ref/index.html');
+  });
+  afterEach(tearDownDom);
+
+  it('ref callback of slot is called', async () => {
+    await waitForChanges();
+
+    const host = app.querySelector('slot-ref');
+    expect(host.getAttribute('data-ref-id')).toBe('slotted-element-id');
+    expect(host.getAttribute('data-ref-tagname')).toBe('SPAN');
+  });
+});