Returns an Awaitable of Vector of ResultOrExceptionWrapper after a mapping operation has been applied to each key/value pair in the provided KeyedTraversable


namespace HH\Asio;

function vmkw<Tk, Tv, Tr>(
  KeyedTraversable<Tk, Tv> $inputs,
  (function(Tk,Tv):Awaitable<Tr>) $callable,
): Awaitable<Vector<HH\Asio\ResultOrExceptionWrapper<Tr>>>;

This function is similar to vmk(), except the Vector in the returned Awaitable contains ResultOrExceptionWrappers instead of raw values.

This function is similar to Vector::mapWithKey(), but the mapping of the key/value pairs are done using Awaitables.

This function is called vmkw because we are returning a vector, doing a mapping operation that includes both keys and values, and each member of the Vector is wrapped by a ResultOrExceptionWrapper.

$callable must return an Awaitable.

The ResultOrExceptionWrappers in the Vector of the returned Awaitable are not available until you await or join the returned Awaitable.


Return Values



namespace Hack\UserDocumentation\API\Examples\HH\Asio\vmkw;

// Map a vector of numbers to their value divided by their index
// throwing on division by zero.
$quotients = \HH\Asio\join(\HH\Asio\vmkw(
  Vector { 1, 2, 6, 12 },

  async ($idx, $val) ==> {
    if ($idx != 0) {
      return $val / $idx;
    } else {
      throw new \Exception("Division by zero: " .
        print_r($val, true) . '/' . print_r($idx, true)

foreach($quotients as $result) {
  if ($result->isSucceeded()) {
    echo "Success: ";
  } else {
    echo "Failed: ";
Failed: string(21) "Division by zero: 1/0"
Success: int(2)
Success: int(3)
Success: int(4)