let async functions return invisibly

r-lib · Aug 21, 2024 · c5b7f95 · c5b7f95
1 parent c29ba7d
commit c5b7f95
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diff --git a/R/generator.R b/R/generator.R
@@ -201,7 +201,7 @@ generator0 <- function(fn, type = "generator") {
         )
         env$jumped <- FALSE
 
-        out
+        invisible(out)
       })
 
       env$.self <- instance

diff --git a/tests/testthat/test-async.R b/tests/testthat/test-async.R
@@ -276,3 +276,14 @@ test_that("can await-assign with `=` (#29)", {
   })
   expect_equal(wait_for(fn()), 2)
 })
+
+test_that("async function returns invisibly (#46)", {
+  out <- NULL
+  fn <- async(function() {
+    for (i in 1:3) {
+      out <<- c(out, i)
+      await(i)
+    }
+  })
+  expect_invisible(fn())
+})