From 15956517803051d14fb3672f4066194b412656fe Mon Sep 17 00:00:00 2001
From: John-David Dalton <john.david.dalton@gmail.com>
Date: Thu, 4 Feb 2016 23:55:55 -0800
Subject: [PATCH] Add support for cloning buffers. [closes #1940]

---
 lodash.js    | 59 +++++++++++++++++++++++++++++++++++++++++++---------
 test/test.js | 17 +++++++++++++++
 2 files changed, 66 insertions(+), 10 deletions(-)

diff --git a/lodash.js b/lodash.js
index 427d385cc..e4d5a4cf2 100644
--- a/lodash.js
+++ b/lodash.js
@@ -230,8 +230,8 @@
 
   /** Used to assign default `context` object properties. */
   var contextProps = [
-    'Array', 'Date', 'Error', 'Float32Array', 'Float64Array', 'Function',
-    'Int8Array', 'Int16Array', 'Int32Array', 'Map', 'Math', 'Object',
+    'Array', 'Buffer', 'Date', 'Error', 'Float32Array', 'Float64Array',
+    'Function', 'Int8Array', 'Int16Array', 'Int32Array', 'Map', 'Math', 'Object',
     'Reflect', 'RegExp', 'Set', 'String', 'Symbol', 'TypeError', 'Uint8Array',
     'Uint8ClampedArray', 'Uint16Array', 'Uint32Array', 'WeakMap', '_',
     'clearTimeout', 'isFinite', 'parseInt', 'setTimeout'
@@ -1305,7 +1305,8 @@
     );
 
     /** Built-in value references. */
-    var Reflect = context.Reflect,
+    var Buffer = moduleExports ? context.Buffer : undefined,
+        Reflect = context.Reflect,
         Symbol = context.Symbol,
         Uint8Array = context.Uint8Array,
         clearTimeout = context.clearTimeout,
@@ -2250,6 +2251,9 @@
         var tag = getTag(value),
             isFunc = tag == funcTag || tag == genTag;
 
+        if (isBuffer(value)) {
+          return cloneBuffer(value);
+        }
         if (tag == objectTag || tag == argsTag || (isFunc && !object)) {
           if (isHostObject(value)) {
             return object ? value : {};
@@ -3707,18 +3711,33 @@
     }
 
     /**
-     * Creates a clone of `buffer`.
+     * Creates a clone of  `buffer`.
      *
      * @private
-     * @param {ArrayBuffer} buffer The array buffer to clone.
-     * @returns {ArrayBuffer} Returns the cloned array buffer.
+     * @param {Buffer} buffer The buffer to clone.
+     * @returns {Buffer} Returns the cloned buffer.
      */
     function cloneBuffer(buffer) {
       var Ctor = buffer.constructor,
-          result = new Ctor(buffer.byteLength),
+          result = new Ctor(buffer.byteLength);
+
+      buffer.copy(result);
+      return result;
+    }
+
+    /**
+     * Creates a clone of `arrayBuffer`.
+     *
+     * @private
+     * @param {ArrayBuffer} arrayBuffer The array buffer to clone.
+     * @returns {ArrayBuffer} Returns the cloned array buffer.
+     */
+    function cloneArrayBuffer(arrayBuffer) {
+      var Ctor = arrayBuffer.constructor,
+          result = new Ctor(arrayBuffer.byteLength),
           view = new Uint8Array(result);
 
-      view.set(new Uint8Array(buffer));
+      view.set(new Uint8Array(arrayBuffer));
       return result;
     }
 
@@ -3784,7 +3803,7 @@
       var buffer = typedArray.buffer,
           Ctor = typedArray.constructor;
 
-      return new Ctor(isDeep ? cloneBuffer(buffer) : buffer, typedArray.byteOffset, typedArray.length);
+      return new Ctor(isDeep ? cloneArrayBuffer(buffer) : buffer, typedArray.byteOffset, typedArray.length);
     }
 
     /**
@@ -4978,7 +4997,7 @@
       var Ctor = object.constructor;
       switch (tag) {
         case arrayBufferTag:
-          return cloneBuffer(object);
+          return cloneArrayBuffer(object);
 
         case boolTag:
         case dateTag:
@@ -9504,6 +9523,26 @@
         (isObjectLike(value) && objectToString.call(value) == boolTag);
     }
 
+    /**
+     * Checks if `value` is a buffer.
+     *
+     * @static
+     * @memberOf _
+     * @category Lang
+     * @param {*} value The value to check.
+     * @returns {boolean} Returns `true` if `value` is a buffer, else `false`.
+     * @example
+     *
+     * _.isBuffer(new Buffer(2));
+     * // => true
+     *
+     * _.isBuffer(new Uint8Array(2));
+     * // => false
+     */
+    var isBuffer = !Buffer ? constant(false) : function(value) {
+      return value instanceof Buffer;
+    };
+
     /**
      * Checks if `value` is classified as a `Date` object.
      *
diff --git a/test/test.js b/test/test.js
index 988df5c81..79fc83e26 100644
--- a/test/test.js
+++ b/test/test.js
@@ -44,6 +44,7 @@
       amd = root.define && define.amd,
       argv = root.process && process.argv,
       ArrayBuffer = root.ArrayBuffer,
+      Buffer = root.Buffer,
       defineProperty = Object.defineProperty,
       document = !phantom && root.document,
       body = root.document && root.document.body,
@@ -2538,6 +2539,22 @@
         assert.strictEqual(actual.lastIndex, 3);
       });
 
+      QUnit.test('`_.' + methodName + '` should clone buffers', function(assert) {
+        assert.expect(3);
+
+        if (Buffer) {
+          var buffer = new Buffer([1, 2, 3]),
+              actual = func(buffer);
+
+          assert.strictEqual(actual.byteLength, buffer.byteLength);
+          assert.strictEqual(actual.inspect(), buffer.inspect());
+          assert.notStrictEqual(actual, buffer);
+        }
+        else {
+          skipTest(assert, 3);
+        }
+      });
+
       QUnit.test('`_.' + methodName + '` should clone prototype objects', function(assert) {
         assert.expect(2);