Any way to use 'defined' operator on object keys?

I have a v-if condition that fails if a state is undefined. The state is nested and pretty large (10k+ entries) and might take time to be constructed. A state's subitem [0].expand of boolean type has to be checked in order to pass the v-if condition:

v-if="
  // condition required to prevent index [0] from failing
  (state.priceClassData[type]
    ? state.priceClassData[type][0].expand
    : false)
  "

I've been trying to refactor this into something more human-readable. In production there are multiple such condition checks in one ternary operator and I am trying to find a way to replace it.

The easiest thing I thought would be to use the ? defined operator on state.priceClassData.type? but as you can see, type in my case is a key and has to be called like so:

state.priceClassData[type][0]

I've not found a way to apply ? here. Other attempts include computed:

const checkCondition = computed(() => {
  if (state.priceClassData[type] && state.priceClassData[type][0]) {
    return state.priceClassData[type][0].expand
  }
  return false
})

but I can't find a way to pass the type parameter into it, making it always return true. I've also tried ordinary functions:

function checkCondition(type) {
  return (state.priceClassData[type] && state.priceClassData[type][0])
    ? state.priceClassData[type][0].expand
    : false
}

but it only seems to be executed initially, returning false and never run again.

I've also tried combining functions and computed:

const checkCondition = (type) => computed(() => {
  return (state.priceClassData[type] && state.priceClassData[type][0])
    ? state.priceClassData[type][0].expand
    : false;
}

which always returns true or:

const checkCondition = computed({
  get() {
    return state.priceClassData
  },
  set() {
    return (state.priceClassData[type] && state.priceClassData[type][0])
    ? state.priceClassData[type][0].expand
    : false;
  }
})

which doesn't seem to accept the syntax.