From 1a1fb93be77634d45c373bf97804ccd074cef719 Mon Sep 17 00:00:00 2001
From: Elliott Marquez <emarquez@google.com>
Date: Mon, 28 Aug 2023 16:26:42 -0700
Subject: [PATCH] feat(select): dispatch select-(open|close)(ing|ed) events

This will allow for the case of data fetching select options only when the select menu has opened.

We prepend the menu events with `select-*` and do not bubble because we have historically had the issue where a select inside a dialog or another menu has had event name clashes causing user runtime issues. I can probably keep them the same names but still not have them bubble if y'all think that's better.

See more discussion in linked github issue

fixes #4798

PiperOrigin-RevId: 560849772
---
 select/internal/select.ts | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/select/internal/select.ts b/select/internal/select.ts
index d4ae7aa3f3..6b533d09d9 100644
--- a/select/internal/select.ts
+++ b/select/internal/select.ts
@@ -26,6 +26,12 @@ const VALUE = Symbol('value');
  * interaction.
  * @fires change Fired when a selection is made by the user via mouse or
  * keyboard interaction.
+ * @fires select-opening Fired when the select's menu is about to open.
+ * @fires select-opened Fired when the select's menu has finished animations and
+ * opened.
+ * @fires select-closing Fired when the select's menu is about to close.
+ * @fires select-closed Fired when the select's menu has finished animations and
+ * closed.
  */
 export abstract class Select extends LitElement {
   /**
@@ -262,7 +268,9 @@ export abstract class Select extends LitElement {
           .fixed=${this.menuFixed}
           .typeaheadDelay=${this.typeaheadDelay}
           @opening=${this.handleOpening}
+          @opened=${this.handleOpened}
           @closing=${this.handleClosing}
+          @closed=${this.handleClosed}
           @close-menu=${this.handleCloseMenu}
           @request-selection=${this.handleRequestSelection}
           @request-deselection=${this.handleRequestDeselection}>
@@ -420,6 +428,8 @@ export abstract class Select extends LitElement {
    * active items.
    */
   private async handleOpening() {
+    this.dispatchEvent(new Event('select-opening'));
+
     const items = this.menu!.items;
     const activeItem = List.getActiveItem(items)?.item;
     const [selectedItem] = this.lastSelectedOptionRecords[0] ?? [null];
@@ -437,8 +447,17 @@ export abstract class Select extends LitElement {
     }
   }
 
+  private handleOpened() {
+    this.dispatchEvent(new Event('select-opened'));
+  }
+
   private handleClosing() {
     this.open = false;
+    this.dispatchEvent(new Event('select-closing'));
+  }
+
+  private handleClosed() {
+    this.dispatchEvent(new Event('select-closed'));
   }
 
   /**