reduce cost of style calc+layout in --dialog-scrollgutter

Co-authored-by: Aaron Ballard <[email protected]> Co-authored-by: AdamShwert <[email protected]> Co-authored-by: Arelia Jones <[email protected]> Co-authored-by: Ariel Valentin <[email protected]> Co-authored-by: Chris Gavin <[email protected]> Co-authored-by: Cody Bodfield <[email protected]> Co-authored-by: Daniel Colson <[email protected]> Co-authored-by: Daniel Garman <[email protected]> Co-authored-by: Dusty Greif <[email protected]> Co-authored-by: Erinna Chen <[email protected]> Co-authored-by: George Brocklehurst <[email protected]> Co-authored-by: Jibran Garcia <[email protected]> Co-authored-by: Jonathan Fuchs <[email protected]> Co-authored-by: Kate Higa <[email protected]> Co-authored-by: Manuel Puyol <[email protected]> Co-authored-by: Matthew Costabile <[email protected]> Co-authored-by: Matthew Reyes <[email protected]> Co-authored-by: Melissa Pastore <[email protected]> Co-authored-by: Ned Schwartz <[email protected]> Co-authored-by: Phill MV <[email protected]> Co-authored-by: Raffaele Di Fazio <[email protected]> Co-authored-by: Sarah Vessels <[email protected]> Co-authored-by: Simon Taranto <[email protected]>
primer · Oct 9, 2024 · 9e8b6fd · 9e8b6fd
1 parent 50fe6a5
commit 9e8b6fd
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Showing 2 changed files with 14 additions and 4 deletions.
diff --git a/app/components/primer/alpha/dialog.pcss b/app/components/primer/alpha/dialog.pcss
@@ -8,6 +8,12 @@
 
 /* Overlay */
 
+@property --dialog-scrollgutter {
+  initial-value: 0;
+  inherits: false;
+  syntax: "<length>";
+}
+
 /* TODO: One day this can be :has(:modal), when it is better supported */
 body.has-modal {
   padding-right: var(--dialog-scrollgutter) !important;

diff --git a/app/components/primer/dialog_helper.ts b/app/components/primer/dialog_helper.ts
@@ -1,4 +1,12 @@
+let dialogScrollGutterSet = false
 function dialogInvokerButtonHandler(event: Event) {
+  if (!dialogScrollGutterSet) {
+    this.ownerDocument.body.style.setProperty(
+      '--dialog-scrollgutter',
+      `${window.innerWidth - this.ownerDocument.body.clientWidth}px`,
+    )
+    dialogScrollGutterSet = true;
+  }
   const target = event.target as HTMLElement
   const button = target?.closest('button')
 
@@ -76,10 +84,6 @@ export class DialogHelperElement extends HTMLElement {
     const {signal} = (this.#abortController = new AbortController())
     document.addEventListener('click', dialogInvokerButtonHandler, true)
     document.addEventListener('click', this, {signal})
-    this.ownerDocument.body.style.setProperty(
-      '--dialog-scrollgutter',
-      `${window.innerWidth - this.ownerDocument.body.clientWidth}px`,
-    )
     new MutationObserver(records => {
       for (const record of records) {
         if (record.target === this.dialog) {