Explain the perf issue

withastro · Nov 30, 2023 · f15a92f · f15a92f
1 parent 974fd2c
commit f15a92f
Showing 1 changed file with 3 additions and 0 deletions.
diff --git a/packages/astro/src/runtime/client/dev-overlay/plugins/utils/highlight.ts b/packages/astro/src/runtime/client/dev-overlay/plugins/utils/highlight.ts
@@ -21,6 +21,9 @@ export function getElementsPositionInDocument(el: Element) {
 	let fixed = false;
 	let current: Element | ParentNode | null = el;
 	while (current instanceof Element) {
+		// This is the expensive part, we are calling getComputedStyle which triggers layout
+		// all the way up the tree. We are only doing so when the app initializes, so the cost is one-time
+		// If perf becomes an issue we'll want to refactor this somehow so that it reads this info in a rAF
 		let style = getComputedStyle(current);
 		let zIndex = Number(style.zIndex);
 		if (!Number.isNaN(zIndex) && zIndex > highestZIndex) {