fix: avoid undefined within development hints

Author: harlan-zw

src/runtime/app/composables/useRobotsRule.ts

@@ -39,12 +39,13 @@ export function useRobotsRule(rule?: MaybeRef<boolean | string>) {
     if (config['nuxt-robots'].header) {
       setHeader(event, 'X-Robots-Tag', _rule)
     }
+    const vmFile = vm?.type?.__file
     useHead({
       meta: [
         {
           'name': 'robots',
           'content': _rule,
-          'data-hint': import.meta.dev ? `useRobotsRule,.${vm ? vm.type?.__file?.split(devRootDir)[1] : ''}` : undefined,
+          'data-hint': import.meta.dev ? ['useRobotsRule', `.${vmFile ? vm.type?.__file?.split(devRootDir)[1] : ''}`].filter(Boolean).join(',') : undefined,
         },
       ],
     }, {

src/runtime/app/plugins/robot-meta.server.ts

@@ -13,7 +13,7 @@ export default defineNuxtPlugin({
         {
           'name': 'robots',
           'content': () => ctx.rule || '',
-          'data-hint': () => import.meta.dev && ctx.debug?.source ? `${ctx.debug?.source},${ctx.debug?.line}` : undefined,
+          'data-hint': () => import.meta.dev && ctx.debug?.source ? [ctx.debug?.source, ctx.debug?.line].filter(Boolean).join(',') : undefined,
         },
       ],
     })