promise_all_settled

NAME

promise_all_settled - wait for every promise and report each outcome

SYNOPSIS

promise promise_all_settled(mixed *promises);

DESCRIPTION

Returns a promise that fulfills once every input has settled -- it never
rejects. The value is an array of one mapping per input, positionally,
describing how that input ended:

    ([ "status": 1, "value":  v ])   fulfilled
    ([ "status": 2, "reason": r ])   rejected
    ([ "status": 3, "reason": r ])   cancelled

The status codes are promise_status(3)'s, so one vocabulary covers both.
A fulfilled entry has no `"reason"` key and a rejected or cancelled
entry has no `"value"` key, so `undefinedp()` distinguishes them as
reliably as `"status"` does.

Use this instead of promise_all(3) when a partial failure is a result
rather than an error -- fanning work out over many objects and reporting
which succeeded, for instance.

An element that is not a promise counts as already fulfilled with
itself, so the output of an ordinary `map()` can be passed straight in.
An empty array fulfills immediately with an empty array.

The name follows JavaScript's `Promise.allSettled`. It is deliberately
not `promise_settle`: that already names the driver's internal "settle
this one promise" operation, and reusing it for "wait for all of these"
would read as almost the opposite.

EXAMPLE

async void reindex(object *rooms) {
    mixed *results = await promise_all_settled(map(rooms, (: $1->rebuild() :)));
    int i;

    foreach (mixed r in results) {
        if (r["status"] != 1) {
            write("room " + i + " failed: " + r["reason"] + "\n");
        }
        i++;
    }
}

SEE ALSO

promise_all(3), promise_any(3), promise_race(3), promise_status(3)