From 7f5bb9d3bf29be8ce65becf4db6ceab78cdd48f3 Mon Sep 17 00:00:00 2001
From: Joyee Cheung <joyeec9h3@gmail.com>
Date: Sat, 3 Nov 2018 03:20:23 +0800
Subject: [PATCH] console: bind methods from the prototype chain in Console

In 62232361 we made the console.Console function construct an object
with methods from Console.prototype bound to the instance, instead of
with methods found on the prototype chain to be bound on the instances,
thus breaking users overriding these methods when subclassing Console
because they are not expecting this function to construct a
namespace whose methods are not looked up from the prototype
chain.

This patch restores the previous behavior since it does not affect
the characteristics of the global console anyway. So after this patch,
the Console function still constructs normal objects with function
properties looked up from the prototype chain but bound to the
instances always.

PR-URL: https://github.com/nodejs/node/pull/24047
Reviewed-By: John-David Dalton <john.david.dalton@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
---
 lib/console.js                         | 5 ++++-
 test/parallel/test-console-instance.js | 6 ++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/lib/console.js b/lib/console.js
index 32713ec5556d03..179acc4a504c9e 100644
--- a/lib/console.js
+++ b/lib/console.js
@@ -132,7 +132,10 @@ function Console(options /* or: stdout, stderr, ignoreErrors = true */) {
   var keys = Object.keys(Console.prototype);
   for (var v = 0; v < keys.length; v++) {
     var k = keys[v];
-    this[k] = Console.prototype[k].bind(this);
+    // We have to bind the methods grabbed from the instance instead of from
+    // the prototype so that users extending the Console can override them
+    // from the prototype chain of the subclass.
+    this[k] = this[k].bind(this);
   }
 }
 
diff --git a/test/parallel/test-console-instance.js b/test/parallel/test-console-instance.js
index 0f1453cb8d0d4b..127e59e6e5b981 100644
--- a/test/parallel/test-console-instance.js
+++ b/test/parallel/test-console-instance.js
@@ -105,10 +105,16 @@ out.write = err.write = (d) => {};
 {
   class MyConsole extends Console {
     hello() {}
+    // See if the methods on Console.prototype are overridable.
+    log() { return 'overridden'; }
   }
   const myConsole = new MyConsole(process.stdout);
   assert.strictEqual(typeof myConsole.hello, 'function');
   assert.ok(myConsole instanceof Console);
+  assert.strictEqual(myConsole.log(), 'overridden');
+
+  const log = myConsole.log;
+  assert.strictEqual(log(), 'overridden');
 }
 
 // Instance that does not ignore the stream errors.