fix(accordion): work around baseclass

Author: bennypowers

elements/pf-accordion/BaseAccordion.ts

@@ -119,6 +119,10 @@ export abstract class BaseAccordion extends LitElement {
     headers.forEach((header, index) => {
       if (header.expanded) {
         this.#expandHeader(header, index);
+        const panel = this.#panelForHeader(header);
+        if (panel) {
+          this.#expandPanel(panel);
+        }
       }
     });
   }

elements/pf-accordion/pf-accordion.ts

@@ -44,6 +44,24 @@ export class PfAccordion extends BaseAccordion {
 
   @property({ type: Boolean, reflect: true }) fixed = false;
 
+  async firstUpdated() {
+    let index: number | null = null;
+    if (this.single) {
+      const allHeaders = [...this.querySelectorAll('pf-accordion-header')];
+      const lastExpanded = allHeaders.filter(x => x.hasAttribute('expanded')).pop();
+      if (lastExpanded) {
+        index = allHeaders.indexOf(lastExpanded);
+      }
+    }
+    await super.firstUpdated();
+    if (index !== null) {
+      this.headers.forEach((_, i) => {
+        this.headers.at(i)?.toggleAttribute('expanded', i === index);
+        this.panels.at(i)?.toggleAttribute('expanded', i === index);
+      });
+    }
+  }
+
   override async expand(index: number, parentAccordion?: BaseAccordion) {
     if (index === -1) {
       return;

elements/pf-accordion/test/pf-accordion.spec.ts

@@ -954,7 +954,7 @@ describe('<pf-accordion>', function() {
       [header, secondHeader] = headers;
       [panel, secondPanel] = panels;
       await allUpdates(element);
-      await nextFrame();
+      await aTimeout(100);
     });
     it('hides the first panel', function() {
       expect(panel).to.not.have.attribute('expanded');
@@ -966,6 +966,7 @@ describe('<pf-accordion>', function() {
       expect(panels[2]).to.not.have.attribute('expanded');
     });
   });
+
   describe('with no h* tag in heading lightdom', function() {
     beforeEach(async function() {
       element = await createFixture<PfAccordion>(html`
@@ -1088,4 +1089,3 @@ describe('<pf-accordion>', function() {
     });
   });
 });
-