util: add callbackify

Add `util.callbackify(function)` for creating callback style functions
from functions returning a `Thenable`

PR-URL: https://github.com/nodejs/node/pull/12712
Fixes: https://github.com/nodejs/CTC/issues/109
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Teddy Katz <teddy.katz@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Timothy Gu <timothygu99@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>

2 files changed, 37 insertions, 0 deletions

diff --git a/test/fixtures/uncaught-exceptions/callbackify1.js b/test/fixtures/uncaught-exceptions/callbackify1.js
new file mode 100644
index 0000000000..1fbe7c8ebf
--- /dev/null
+++ b/test/fixtures/uncaught-exceptions/callbackify1.js
@@ -0,0 +1,15 @@
+'use strict';
+
+// Used to test that `uncaughtException` is emitted
+
+const { callbackify } = require('util');
+
+{
+  async function fn() { }
+
+  const cbFn = callbackify(fn);
+
+  cbFn((err, ret) => {
+    throw new Error(__filename);
+  });
+}
diff --git a/test/fixtures/uncaught-exceptions/callbackify2.js b/test/fixtures/uncaught-exceptions/callbackify2.js
new file mode 100644
index 0000000000..9080da234f
--- /dev/null
+++ b/test/fixtures/uncaught-exceptions/callbackify2.js
@@ -0,0 +1,22 @@
+'use strict';
+
+// Used to test the `uncaughtException` err object
+
+const assert = require('assert');
+const { callbackify } = require('util');
+
+{
+  const sentinel = new Error(__filename);
+  process.once('uncaughtException', (err) => {
+    assert.strictEqual(err, sentinel);
+    // Calling test will use `stdout` to assert value of `err.message`
+    console.log(err.message);
+  });
+
+  async function fn() {
+    return await Promise.reject(sentinel);
+  }
+
+  const cbFn = callbackify(fn);
+  cbFn((err, ret) => assert.ifError(err));
+}