hphp/hack/manual/hsl/Functions/HH.Lib.Dict/from_async.md
:::info[Note] This is a point-in-time snapshot of the API documentation from January 2026. Going forward, we will not be maintaining a public copy of these references, and recommend users to refer to the built-in signature helpers available in the Hack LSP instead for complete and up-to-date information. :::
Returns a new dict with each value awaited in parallel
namespace HH\Lib\Dict;
function from_async<Tk as arraykey, Tv>(
KeyedTraversable<Tk, Awaitable<Tv>> $awaitables,
): Awaitable<dict<Tk, Tv>>;
Time complexity: O(n * a), where a is the complexity of the synchronous portions of each Awaitable Space complexity: O(n)
The IO operations for each Awaitable will happen in parallel.
KeyedTraversable<Tk,Awaitable<Tv>> $awaitables