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% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/utils.R
\name{promise_all}
\alias{promise_all}
\alias{promise_race}
\title{Combine multiple promise objects}
\usage{
promise_all(..., .list = NULL)
promise_race(..., .list = NULL)
}
\arguments{
\item{...}{Promise objects. Either all arguments must be named, or all
arguments must be unnamed. If \code{.list} is provided, then these arguments are
ignored.}
\item{.list}{A list of promise objects--an alternative to \code{...}.}
}
\value{
A promise.
For \code{promise_all}, if all of the promises were successful, the returned
promise will resolve to a list of the promises' values; if any promise
fails, the first error to be encountered will be used to reject the
returned promise.
For \code{promise_race}, the first of the promises to either fulfill or reject
will be passed through to the returned promise.
}
\description{
Use \code{promise_all} to wait for multiple promise objects to all be successfully
fulfilled. Use \code{promise_race} to wait for the first of multiple promise
objects to be either fulfilled or rejected.
}
\examples{
p1 <- promise(~later::later(~resolve(1), delay = 1))
p2 <- promise(~later::later(~resolve(2), delay = 2))
# Resolves after 1 second, to the value: 1
promise_race(p1, p2) \%...>\% {
cat("promise_race:\\n")
str(.)
}
# Resolves after 2 seconds, to the value: list(1, 2)
promise_all(p1, p2) \%...>\% {
cat("promise_all:\\n")
str(.)
}
}
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