From 29130742c95fc5883c636255613636fcec22544f Mon Sep 17 00:00:00 2001
From: Shadowbeetle <tamas.kadlecsik@gmail.com>
Date: Thu, 18 May 2017 10:09:50 +0200
Subject: [PATCH] async_hooks: add constructor check to async-hooks

This fixes the async_hooks.AsyncHook constructor such that it throws an error
when provided with falsy values other than undefined.
---
 lib/async_hooks.js                           |  8 ++++----
 test/parallel/test-async-wrap-constructor.js | 12 ++++++++++++
 2 files changed, 16 insertions(+), 4 deletions(-)
 create mode 100644 test/parallel/test-async-wrap-constructor.js

diff --git a/lib/async_hooks.js b/lib/async_hooks.js
index 867b5eb52da14d..9ff244aad7e6b4 100644
--- a/lib/async_hooks.js
+++ b/lib/async_hooks.js
@@ -77,13 +77,13 @@ function fatalError(e) {
 
 class AsyncHook {
   constructor({ init, before, after, destroy }) {
-    if (init && typeof init !== 'function')
+    if (init !== undefined && typeof init !== 'function')
       throw new TypeError('init must be a function');
-    if (before && typeof before !== 'function')
+    if (before !== undefined && typeof before !== 'function')
       throw new TypeError('before must be a function');
-    if (after && typeof after !== 'function')
+    if (after !== undefined && typeof after !== 'function')
       throw new TypeError('after must be a function');
-    if (destroy && typeof destroy !== 'function')
+    if (destroy !== undefined && typeof destroy !== 'function')
       throw new TypeError('destroy must be a function');
 
     this[init_symbol] = init;
diff --git a/test/parallel/test-async-wrap-constructor.js b/test/parallel/test-async-wrap-constructor.js
new file mode 100644
index 00000000000000..213691a7808692
--- /dev/null
+++ b/test/parallel/test-async-wrap-constructor.js
@@ -0,0 +1,12 @@
+'use strict';
+require('../common');
+const assert = require('assert');
+const async_hooks = require('async_hooks');
+
+for (const badArg of [0, 1, false, true, null, 'hello']) {
+  for (const field of ['init', 'before', 'after', 'destroy']) {
+    assert.throws(() => {
+      async_hooks.createHook({ [field]: badArg });
+    }, new RegExp(`^TypeError: ${field} must be a function$`));
+  }
+}