From 72645ef225f9a98ff7c11600af080cd6e7671f8c Mon Sep 17 00:00:00 2001
From: Justin Ridgewell <justin@ridgewell.name>
Date: Thu, 18 Jun 2015 11:38:45 -0400
Subject: [PATCH 1/2] Use Function#bind when available

---
 underscore.js | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/underscore.js b/underscore.js
index c8d534b10..460f155b7 100644
--- a/underscore.js
+++ b/underscore.js
@@ -17,12 +17,13 @@
   var previousUnderscore = root._;
 
   // Save bytes in the minified (but not gzipped) version:
-  var ArrayProto = Array.prototype, ObjProto = Object.prototype;
+  var ArrayProto = Array.prototype, FuncProto = Function.prototype, ObjProto = Object.prototype;
 
   // Create quick reference variables for speed access to core prototypes.
   var
     push = ArrayProto.push,
     slice = ArrayProto.slice,
+    bind = FuncProto.bind,
     toString = ObjProto.toString,
     hasOwnProperty = ObjProto.hasOwnProperty;
 
@@ -712,7 +713,9 @@
   // Create a function bound to a given object (assigning `this`, and arguments,
   // optionally). Delegates to **ECMAScript 5**'s native `Function.bind` if
   // available.
-  _.bind = restArgs(function(func, context, args) {
+  _.bind = bind ? restArgs(function(func, args) {
+      return bind.apply(func, args);
+  }) : restArgs(function(func, context, args) {
     if (!_.isFunction(func)) throw new TypeError('Bind must be called on a function');
     var bound = restArgs(function(callArgs) {
       return executeBound(func, bound, context, this, args.concat(callArgs));

From 2a11f8754aecb5481a62771f40c78a22fb757afe Mon Sep 17 00:00:00 2001
From: Julian Gonggrijp <dev@juliangonggrijp.com>
Date: Sun, 3 May 2020 04:14:57 +0200
Subject: [PATCH 2/2] Add a test to expose #2214

---
 test/functions.js | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/test/functions.js b/test/functions.js
index f037b996c..89bd0b119 100644
--- a/test/functions.js
+++ b/test/functions.js
@@ -46,6 +46,12 @@
     assert.strictEqual(boundf().hello, 'moe curly', "When called without the new operator, it's OK to be bound to the context");
     assert.ok(newBoundf instanceof F, 'a bound instance is an instance of the original function');
 
+    // Ensure that we are not reproducing #2214.
+    var D = _.bind(Date, null, 2015, 5);
+    var newD = new D(10);
+    assert.ok(newD instanceof Date, 'works on variable argument constructors');
+    assert.ok(newD.toISOString(), 'works on nontrivial constructors');
+
     assert.raises(function() { _.bind('notafunction'); }, TypeError, 'throws an error when binding to a non-function');
   });