vue: Uncaught TypeError: Cannot read property … of undefined

Just use v-if on a common parent to all the elements in your template relying on that AJAX call, not around each one.

So instead of something like:

<div>
  <h1 v-if="foo.title">{{ foo.title }}</h1>
  <p v-if="foo.description">{{ foo.description }}</p>
</div>

Do

<div>
  <template v-if="foo">
    <h1>{{ foo.title }}</h1>
    <p>{{ foo.description }}</p>
  </template>
</div>