(vue) - Refactor lazy promise and watch effects

[kitten]

Summary

This refactors useQuery to use watchEffect again (see earlier commits). It then goes further to ensure that the lazy promise will always look at the latest query that has been issued. It also ensures that this latest query is shared if it's ongoing and not if it's completed. A paused query will always immediately resolve the latest result.

This implementation is made a lot easier by the fact that we're resolving to the same state object every time. Since there's only one truth for the state, we don't need to ensure that the streams are transformed to usable scan state like in react-urql.

Set of changes

• Use a continuous subject to track the latest query stream
• Make all ref updates side-effects of these query streams as they're issued
• Write a replayOne operator to wrap the subject stream with
• Derive current state as one continuous switchAll on the replayOne subject stream
• Derive lazy promise from a switchAll then take(1) on the replayOne subject stream
• Refactor used effects back to watchEffect

cc @LinusBorg: This should tick all the boxes for you 🙌

[changeset-bot]

🦋 Changeset detected

Latest commit: bc2290a

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@urql/vue	Minor

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR