fix: useFetch not returning fetch and fetchState on SSR

[toddheslin]

🐛 The bug
OK this might be intentional but it might be worth a discussion

I was previously using 0.9.3 and had a composition function that looked like this:

const { fetch, fetchState } = useFetch(async () => {
    data.value = await hasura
      .query({ query: query.query })
      .then(select(query.returning))
  })

After upgrading to 0.10.3 I found that on server rendering useFetch() was returning undefined and therefore my destructuring would throw and error. However, all would be OK when mounting the component on the client side only.

Given that the docs use the example:

const { fetch, fetchState } = useFetch(async () => {
      name.value = await axios.get('https://myapi.com/name')
})

I'm wondering if this is intentional, or a regression.

🛠️ To reproduce
Use the example useFetch() in the docs using 0.10.3 and check if error 'Can not structured from undefined` shows on server render.

🌈 Expected behaviour
useFetch() always returns and object with fetch and fetchState properties, on both client and server.

ℹ️ Additional context
I am using this inside a separate file, I don't think this matters but will detail below:

index.vue

<script>
import { defineComponent, ref } from 'nuxt-composition-api'
import { useQuery, ALL_LOUNGES } from '@/data'

export default defineComponent({
  layout: 'collection',
  setup() {
    const activeTab = ref('London Heathrow')

    const { lounges, fetch, fetchState } = useQuery(ALL_LOUNGES)

    return { lounges, activeTab }
  },
})
</script>

@/data

// imports and some utility functions above
function useQuery(query) {
  const { app } = useContext()
  const hasura = app.apolloProvider.defaultClient

  const data = ssrRef(false)

  const { fetch, fetchState } = useFetch(async () => {
    data.value = await hasura
      .query({ query: query.query })
      .then(select(query.returning))
  })

  return { fetch, fetchState, [query.returning]: data }
}

export { useQuery }

[danielroe]

@toddheslin This should be fixed in 0.10.4. Apologies for the regression!