useSuspenseCondition()

[ntucker]

This is for long-running tasks that don't resolve from a simple fetch. Endpoint is subscribed (meaning they can use polling or other methods like websockets); then on updates - they check a conditional (function set in endpoint) and if does not pass, throws a promise for next polling frequency.

This will be used for workflow result stream. By using suspense in react 18 the entire flow is very simple - useTransition can simply be used on the workflow button to grab next results.

const WFR = endpoint.extend({ condition: (response) => response.status === 'done' })

const workflowResults = useSuspenseCondition(WFR, { id })

const [isPending, startTransition] = useTransition();
const handleRun = useCallback(

[ntucker]

Instead, we can introduce useSuspenseQuery(), which is like useQuery() but suspends until the query is not undefined or INVALID.

The workflow above could be implemented by creating a query that returns 'undefined' unless the status === 'done'.

const workflowDone = new schema.Query(Workflow, (workflow) => workflow.status === 'done' ? undefined : true);

This also enables 'fallback queries' to eliminate the nasty undefined conditional:

const queryPrice = new schema.Query(
  { ticker: Ticker, stats: Stats },
  ({ ticker, stats }) => ticker?.price ?? stats?.last,
);

function AssetPrice({ product_id }) {
  const price = useQuery(queryPrice, { product_id });
  if (!price) return <span></span>;
}

const queryPrice = new schema.Query(
  { ticker: Ticker, stats: Stats },
  ({ ticker, stats }) => ticker?.price ?? stats?.last,
);

function AssetPrice({ product_id }) {
  const price = useSuspenseQuery(queryPrice, { product_id });
}