CurrencyAsyncResolver

Fetches exchange rates before the VM runs, so a conversion has real numbers.

Until rates arrive the line evaluates to a pending value rather than a guessed one, and re-evaluates when they land.

Implements

new CurrencyAsyncResolver(exchange?): CurrencyAsyncResolver;

Parameter	Type
`exchange?`	`CurrencyExchangeService`

CurrencyAsyncResolver

readonly namespace: "currency" = CURRENCY_NS;

Unique namespace for cache key scoping (e.g., “currency”, “weather”)

destroy(): void;

Called when the resolver’s namespace is being unregistered. Clean up any in-flight promises, clear caches, unsubscribe.

void

preflight(
   _tokens,
   bytecode,
   packageId,
   signal,
   queryClient):
  | AsyncCheckResult
  | null;

Pre-flight check: called BEFORE VM execution.

Returns null if all data for this expression is cached and ready. Returns an AsyncCheckResult if async work is needed.

This method is synchronous, it only checks caches, never fetches. If data is missing, it creates a Promise and returns immediately.

Parameter	Type	Description
`_tokens`	`Token`[]	-
`bytecode`	`BytecodeProgram`	The compiled bytecode program
`packageId`	`string`	-
`signal`	`AbortSignal`	AbortSignal for the current evaluation
`queryClient`	`QueryClient`	-