Function: prepareChart()
prepareChart(
opts):Promise<{chartId:string;marker:string; }>
Mint a chartId, cache an empty { chartId } placeholder
synchronously, and kick off a background task that resolves the
dataset and runs the planner. Returns the chartId once the
placeholder lands so the first fetchChart call always
sees an entry (no spurious 404 race).
The background task swallows its own failures and writes them
as error entries, so callers never see a rejected promise.
Cache state machine:
- just after this call returns:
{ chartId }(processing) - on planner success:
{ chartId, result } - on data / planner failure:
{ chartId, error }
Parameters
Section titled “Parameters”Returns
Section titled “Returns”Promise<{ chartId: string; marker: string; }>