Fix: binding.value could be undefined, in that case we should manage to avoid an error when is trying to transform into string

Author: sfe-efficy

packages/bootstrap-vue-3/src/directives/BTooltip.ts

@@ -65,7 +65,7 @@ const resolveDelay = (values: DirectiveBinding['value']): Tooltip.Options['delay
   return 0
 }
 
-const resolveTitle = (values: DirectiveBinding['value']): Tooltip.Options['title'] =>
+const resolveTitle = (values: DirectiveBinding['value']): Tooltip.Options['title'] | undefined =>
   typeof values === 'object' ? values?.title : values
 
 /**
@@ -75,7 +75,7 @@ const BTooltip: Directive<HTMLElement> = {
   beforeMount(el, binding) {
     el.setAttribute('data-bs-toggle', 'tooltip')
     if (!el.getAttribute('title')) {
-      el.setAttribute('title', resolveTitle(binding.value).toString())
+      el.setAttribute('title', resolveTitle(binding.value)?.toString())
     }
 
     const isHtml = /<("[^"]*"|'[^']*'|[^'">])*>/.test(el.title)
@@ -97,7 +97,7 @@ const BTooltip: Directive<HTMLElement> = {
   },
   updated(el, binding) {
     if (!el.getAttribute('title')) {
-      el.setAttribute('title', resolveTitle(binding.value).toString())
+      el.setAttribute('title', resolveTitle(binding.value)?.toString())
     }
 
     const title = el.getAttribute('title')