feat: add "unhandledrejection" event support (#12994)

This commit adds support for "unhandledrejection" event.

This event will trigger event listeners registered using:

"globalThis.addEventListener("unhandledrejection")
"globalThis.onunhandledrejection"
This is done by registering a default handler using
"Deno.core.setPromiseRejectCallback" that allows to
handle rejected promises in JavaScript instead of Rust.

This commit will make it possible to polyfill
"process.on("unhandledRejection")" in the Node compat
layer.

Co-authored-by: Colin Ihrig <cjihrig@gmail.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/core/ops_builtin.rs b/core/ops_builtin.rs
index a42c0bae8..53f2bd706 100644
--- a/core/ops_builtin.rs
+++ b/core/ops_builtin.rs
@@ -38,6 +38,7 @@ pub(crate) fn init_builtins() -> Extension {
       op_metrics::decl(),
       op_format_file_name::decl(),
       op_is_proxy::decl(),
+      op_next_task::decl(),
     ])
     .ops(crate::ops_builtin_v8::init_builtins_v8())
     .build()
@@ -189,3 +190,8 @@ fn op_format_file_name(file_name: String) -> String {
 fn op_is_proxy(value: serde_v8::Value) -> bool {
   value.v8_value.is_proxy()
 }
+
+/// Empty op that when awaited forces a macrotask to run. Useful for
+/// "unhandledrejection" event.
+#[op]
+async fn op_next_task() {}