Fix #24 - Add additional undefined transition check for Firefox 124

Author: smastrom

packages/vue-collapsed/src/utils.ts

@@ -4,6 +4,8 @@ import type { Ref } from 'vue'
 
 type RefEl = Ref<HTMLElement | null>
 
+const isFirefox = () => typeof navigator !== 'undefined' && navigator.userAgent.includes('Firefox')
+
 export function getComputedHeight(el: RefEl) {
    if (!el.value) return 0
    return parseFloat(getComputedStyle(el.value).height)
@@ -20,8 +22,14 @@ export function getTransitionProp(el: RefEl) {
 
    const { transition } = getComputedStyle(el.value)
 
-   // If transition is not defined, return the default one
-   if (transition === 'all 0s ease 0s') return { transition: DEFAULT_TRANSITION }
+   // If transition is not defined via CSS, return the default one referencing the auto duration
+   if (
+      transition === 'all 0s ease 0s' ||
+      (isFirefox() &&
+         transition ===
+            'all') /* Since Firefox v124, Gecko returns transition 'all' instead of 'all 0s ease 0s' */
+   )
+      return { transition: DEFAULT_TRANSITION }
 
    return { transition }
 }