node: process.on("beforeExit")

node/_core.ts

@@ -22,5 +22,8 @@ if (Deno?.core) {
     encode(chunk: string): Uint8Array {
       return new TextEncoder().encode(chunk);
     },
+    eventLoopHasMoreWork(): boolean {
+      return false;
+    },
   };
 }

node/_next_tick.ts

@@ -18,6 +18,56 @@ const queue = new FixedQueue();
 // deno-lint-ignore no-explicit-any
 let _nextTick: any;
 
+export function processTicksAndRejections() {
+  let tock;
+  do {
+    // deno-lint-ignore no-cond-assign
+    while (tock = queue.shift()) {
+      // FIXME(bartlomieju): Deno currently doesn't support async hooks
+      // const asyncId = tock[async_id_symbol];
+      // emitBefore(asyncId, tock[trigger_async_id_symbol], tock);
+
+      try {
+        const callback = (tock as Tock).callback;
+        if ((tock as Tock).args === undefined) {
+          callback();
+        } else {
+          const args = (tock as Tock).args;
+          switch (args.length) {
+            case 1:
+              callback(args[0]);
+              break;
+            case 2:
+              callback(args[0], args[1]);
+              break;
+            case 3:
+              callback(args[0], args[1], args[2]);
+              break;
+            case 4:
+              callback(args[0], args[1], args[2], args[3]);
+              break;
+            default:
+              callback(...args);
+          }
+        }
+      } finally {
+        // FIXME(bartlomieju): Deno currently doesn't support async hooks
+        // if (destroyHooksExist())
+        // emitDestroy(asyncId);
+      }
+
+      // FIXME(bartlomieju): Deno currently doesn't support async hooks
+      // emitAfter(asyncId);
+    }
+    core.runMicrotasks();
+    // FIXME(bartlomieju): Deno currently doesn't unhandled rejections
+    // } while (!queue.isEmpty() || processPromiseRejections());
+  } while (!queue.isEmpty());
+  core.setHasTickScheduled(false);
+  // FIXME(bartlomieju): Deno currently doesn't unhandled rejections
+  // setHasRejectionToWarn(false);
+}
+
 if (typeof core.setNextTickCallback !== "undefined") {
   function runNextTicks() {
     // FIXME(bartlomieju): Deno currently doesn't unhandled rejections
@@ -36,56 +86,6 @@ if (typeof core.setNextTickCallback !== "undefined") {
     return true;
   }
 
-  function processTicksAndRejections() {
-    let tock;
-    do {
-      // deno-lint-ignore no-cond-assign
-      while (tock = queue.shift()) {
-        // FIXME(bartlomieju): Deno currently doesn't support async hooks
-        // const asyncId = tock[async_id_symbol];
-        // emitBefore(asyncId, tock[trigger_async_id_symbol], tock);
-
-        try {
-          const callback = (tock as Tock).callback;
-          if ((tock as Tock).args === undefined) {
-            callback();
-          } else {
-            const args = (tock as Tock).args;
-            switch (args.length) {
-              case 1:
-                callback(args[0]);
-                break;
-              case 2:
-                callback(args[0], args[1]);
-                break;
-              case 3:
-                callback(args[0], args[1], args[2]);
-                break;
-              case 4:
-                callback(args[0], args[1], args[2], args[3]);
-                break;
-              default:
-                callback(...args);
-            }
-          }
-        } finally {
-          // FIXME(bartlomieju): Deno currently doesn't support async hooks
-          // if (destroyHooksExist())
-          // emitDestroy(asyncId);
-        }
-
-        // FIXME(bartlomieju): Deno currently doesn't support async hooks
-        // emitAfter(asyncId);
-      }
-      core.runMicrotasks();
-      // FIXME(bartlomieju): Deno currently doesn't unhandled rejections
-      // } while (!queue.isEmpty() || processPromiseRejections());
-    } while (!queue.isEmpty());
-    core.setHasTickScheduled(false);
-    // FIXME(bartlomieju): Deno currently doesn't unhandled rejections
-    // setHasRejectionToWarn(false);
-  }
-
   core.setNextTickCallback(processTicksAndRejections);
   core.setMacrotaskCallback(runNextTicks);
 

node/_tools/config.json

@@ -407,8 +407,10 @@
       "test-path-win32-exists.js",
       "test-path-zero-length-strings.js",
       "test-path.js",
+      "test-process-beforeexit.js",
       "test-process-binding-internalbinding-allowlist.js",
       "test-process-env-allowed-flags.js",
+      "test-process-exit-from-before-exit.js",
       "test-process-exit-handler.js",
       "test-process-exit-recursive.js",
       "test-process-exit.js",

node/_tools/test/parallel/test-process-beforeexit.js

@@ -0,0 +1,79 @@
+// deno-fmt-ignore-file
+// deno-lint-ignore-file
+
+// Copyright Joyent and Node contributors. All rights reserved. MIT license.
+// Taken from Node 16.13.0
+// This file is automatically generated by "node/_tools/setup.ts". Do not modify this file manually
+
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+'use strict';
+const common = require('../common');
+const net = require('net');
+
+process.once('beforeExit', common.mustCall(tryImmediate));
+
+function tryImmediate() {
+  setImmediate(common.mustCall(() => {
+    process.once('beforeExit', common.mustCall(tryTimer));
+  }));
+}
+
+function tryTimer() {
+  setTimeout(common.mustCall(() => {
+    process.once('beforeExit', common.mustCall(tryListen));
+  }), 1);
+}
+
+function tryListen() {
+  net.createServer()
+    .listen(0)
+    .on('listening', common.mustCall(function() {
+      this.close();
+      process.once('beforeExit', common.mustCall(tryRepeatedTimer));
+    }));
+}
+
+// Test that a function invoked from the beforeExit handler can use a timer
+// to keep the event loop open, which can use another timer to keep the event
+// loop open, etc.
+//
+// After N times, call function `tryNextTick` to test behaviors of the
+// `process.nextTick`.
+function tryRepeatedTimer() {
+  const N = 5;
+  let n = 0;
+  const repeatedTimer = common.mustCall(function() {
+    if (++n < N)
+      setTimeout(repeatedTimer, 1);
+    else // n == N
+      process.once('beforeExit', common.mustCall(tryNextTick));
+  }, N);
+  setTimeout(repeatedTimer, 1);
+}
+
+// Test if the callback of `process.nextTick` can be invoked.
+function tryNextTick() {
+  process.nextTick(common.mustCall(function() {
+    process.once('beforeExit', common.mustNotCall());
+  }));
+}

node/_tools/test/parallel/test-process-exit-from-before-exit.js

@@ -0,0 +1,37 @@
+// deno-fmt-ignore-file
+// deno-lint-ignore-file
+
+// Copyright Joyent and Node contributors. All rights reserved. MIT license.
+// Taken from Node 16.13.0
+// This file is automatically generated by "node/_tools/setup.ts". Do not modify this file manually
+
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+'use strict';
+const common = require('../common');
+const assert = require('assert');
+
+process.on('beforeExit', common.mustCall(function() {
+  setTimeout(common.mustNotCall(), 5);
+  process.exit(0);  // Should execute immediately even if we schedule new work.
+  assert.fail();
+}));

node/process.ts

@@ -36,6 +36,9 @@ import {
   stdin as stdin_,
   stdout as stdout_,
 } from "./_process/streams.mjs";
+import { core } from "./_core.ts";
+import { processTicksAndRejections } from "./_next_tick.ts";
+
 // TODO(kt3k): Give better types to stdio objects
 // deno-lint-ignore no-explicit-any
 const stderr = stderr_ as any;
@@ -49,7 +52,6 @@ import type { BindingName } from "./internal_binding/mod.ts";
 import { buildAllowedFlags } from "./internal/process/per_thread.mjs";
 
 const notImplementedEvents = [
-  "beforeExit",
   "disconnect",
   "message",
   "multipleResolves",
@@ -89,6 +91,9 @@ export const exit = (code?: number | string) => {
 
   if (!process._exiting) {
     process._exiting = true;
+    // FIXME(bartlomieju): this is wrong, we won't be using syscall to exit
+    // and thus the `unload` event will not be emitted to properly trigger "emit"
+    // event on `process`.
     process.emit("exit", process.exitCode || 0);
   }
 
@@ -266,6 +271,14 @@ class Process extends EventEmitter {
   constructor() {
     super();
 
+    globalThis.addEventListener("beforeunload", (e) => {
+      super.emit("beforeExit", process.exitCode || 0);
+      processTicksAndRejections();
+      if (core.eventLoopHasMoreWork()) {
+        e.preventDefault();
+      }
+    });
+
     globalThis.addEventListener("unload", () => {
       if (!process._exiting) {
         process._exiting = true;