diff --git a/src/runtime/transition/index.ts b/src/runtime/transition/index.ts
index 4df9179003..740564c3b2 100644
--- a/src/runtime/transition/index.ts
+++ b/src/runtime/transition/index.ts
@@ -117,7 +117,7 @@ export function slide(node: Element, {
 	const margin_first_value = parseFloat(style.margin + secondary_dimensions[0]);
 	const margin_second_value = parseFloat(style.margin + secondary_dimensions[1]);
 	const border_width_first_value = parseFloat(style['border'.concat(secondary_dimensions[0].concat('Width'))]);
-	const border_width_second_value = parseFloat(style['border'.concat(secondary_dimensions[1].concat('Width'))]);
+	const border_width_second_value = parseFloat(style[`border${secondary_dimensions[1]}Width`]);
 	return {
 		delay,
 		duration,