Remove unneeded that parameter

Thanks for pointing this out, @jdalton.

index.js

@@ -51,14 +51,14 @@ function typedArraySupport () {
   }
 }
 
-function createBuffer (that, length) {
+function createBuffer (length) {
   if (K_MAX_LENGTH < length) {
     throw new RangeError('Invalid typed array length')
   }
   // Return an augmented `Uint8Array` instance
-  that = new Uint8Array(length)
-  that.__proto__ = Buffer.prototype
-  return that
+  var buf = new Uint8Array(length)
+  buf.__proto__ = Buffer.prototype
+  return buf
 }
 
 /**
@@ -79,9 +79,9 @@ function Buffer (arg, encodingOrOffset, length) {
         'If encoding is specified then the first argument must be a string'
       )
     }
-    return allocUnsafe(this, arg)
+    return allocUnsafe(arg)
   }
-  return from(this, arg, encodingOrOffset, length)
+  return from(arg, encodingOrOffset, length)
 }
 
 Buffer.prototype.__proto__ = Uint8Array.prototype
@@ -100,20 +100,20 @@ if (typeof Symbol !== 'undefined' && Symbol.species &&
 
 Buffer.poolSize = 8192 // not used by this implementation
 
-function from (that, value, encodingOrOffset, length) {
+function from (value, encodingOrOffset, length) {
   if (typeof value === 'number') {
     throw new TypeError('"value" argument must not be a number')
   }
 
   if (typeof ArrayBuffer !== 'undefined' && value instanceof ArrayBuffer) {
-    return fromArrayBuffer(that, value, encodingOrOffset, length)
+    return fromArrayBuffer(value, encodingOrOffset, length)
   }
 
   if (typeof value === 'string') {
-    return fromString(that, value, encodingOrOffset)
+    return fromString(value, encodingOrOffset)
   }
 
-  return fromObject(that, value)
+  return fromObject(value)
 }
 
 /**
@@ -125,7 +125,7 @@ function from (that, value, encodingOrOffset, length) {
  * Buffer.from(arrayBuffer[, byteOffset[, length]])
  **/
 Buffer.from = function (value, encodingOrOffset, length) {
-  return from(null, value, encodingOrOffset, length)
+  return from(value, encodingOrOffset, length)
 }
 
 function assertSize (size) {
@@ -136,49 +136,49 @@ function assertSize (size) {
   }
 }
 
-function alloc (that, size, fill, encoding) {
+function alloc (size, fill, encoding) {
   assertSize(size)
   if (size <= 0) {
-    return createBuffer(that, size)
+    return createBuffer(size)
   }
   if (fill !== undefined) {
     // Only pay attention to encoding if it's a string. This
     // prevents accidentally sending in a number that would
     // be interpretted as a start offset.
     return typeof encoding === 'string'
-      ? createBuffer(that, size).fill(fill, encoding)
-      : createBuffer(that, size).fill(fill)
+      ? createBuffer(size).fill(fill, encoding)
+      : createBuffer(size).fill(fill)
   }
-  return createBuffer(that, size)
+  return createBuffer(size)
 }
 
 /**
  * Creates a new filled Buffer instance.
  * alloc(size[, fill[, encoding]])
  **/
 Buffer.alloc = function (size, fill, encoding) {
-  return alloc(null, size, fill, encoding)
+  return alloc(size, fill, encoding)
 }
 
-function allocUnsafe (that, size) {
+function allocUnsafe (size) {
   assertSize(size)
-  return createBuffer(that, size < 0 ? 0 : checked(size) | 0)
+  return createBuffer(size < 0 ? 0 : checked(size) | 0)
 }
 
 /**
  * Equivalent to Buffer(num), by default creates a non-zero-filled Buffer instance.
  * */
 Buffer.allocUnsafe = function (size) {
-  return allocUnsafe(null, size)
+  return allocUnsafe(size)
 }
 /**
  * Equivalent to SlowBuffer(num), by default creates a non-zero-filled Buffer instance.
  */
 Buffer.allocUnsafeSlow = function (size) {
-  return allocUnsafe(null, size)
+  return allocUnsafe(size)
 }
 
-function fromString (that, string, encoding) {
+function fromString (string, encoding) {
   if (typeof encoding !== 'string' || encoding === '') {
     encoding = 'utf8'
   }
@@ -188,30 +188,30 @@ function fromString (that, string, encoding) {
   }
 
   var length = byteLength(string, encoding) | 0
-  that = createBuffer(that, length)
+  var buf = createBuffer(length)
 
-  var actual = that.write(string, encoding)
+  var actual = buf.write(string, encoding)
 
   if (actual !== length) {
     // Writing a hex string, for example, that contains invalid characters will
     // cause everything after the first invalid character to be ignored. (e.g.
     // 'abxxcd' will be treated as 'ab')
-    that = that.slice(0, actual)
+    buf = buf.slice(0, actual)
   }
 
-  return that
+  return buf
 }
 
-function fromArrayLike (that, array) {
+function fromArrayLike (array) {
   var length = array.length < 0 ? 0 : checked(array.length) | 0
-  that = createBuffer(that, length)
+  var buf = createBuffer(length)
   for (var i = 0; i < length; i += 1) {
-    that[i] = array[i] & 255
+    buf[i] = array[i] & 255
   }
-  return that
+  return buf
 }
 
-function fromArrayBuffer (that, array, byteOffset, length) {
+function fromArrayBuffer (array, byteOffset, length) {
   array.byteLength // this throws if `array` is not a valid ArrayBuffer
 
   if (byteOffset < 0 || array.byteLength < byteOffset) {
@@ -222,44 +222,44 @@ function fromArrayBuffer (that, array, byteOffset, length) {
     throw new RangeError('\'length\' is out of bounds')
   }
 
+  var buf
   if (byteOffset === undefined && length === undefined) {
-    array = new Uint8Array(array)
+    buf = new Uint8Array(array)
   } else if (length === undefined) {
-    array = new Uint8Array(array, byteOffset)
+    buf = new Uint8Array(array, byteOffset)
   } else {
-    array = new Uint8Array(array, byteOffset, length)
+    buf = new Uint8Array(array, byteOffset, length)
   }
 
-  // Return an augmented `Uint8Array` instance, for best performance
-  that = array
-  that.__proto__ = Buffer.prototype
-  return that
+  // Return an augmented `Uint8Array` instance
+  buf.__proto__ = Buffer.prototype
+  return buf
 }
 
-function fromObject (that, obj) {
+function fromObject (obj) {
   if (Buffer.isBuffer(obj)) {
     var len = checked(obj.length) | 0
-    that = createBuffer(that, len)
+    var buf = createBuffer(len)
 
-    if (that.length === 0) {
-      return that
+    if (buf.length === 0) {
+      return buf
     }
 
-    obj.copy(that, 0, 0, len)
-    return that
+    obj.copy(buf, 0, 0, len)
+    return buf
   }
 
   if (obj) {
     if ((typeof ArrayBuffer !== 'undefined' &&
         obj.buffer instanceof ArrayBuffer) || 'length' in obj) {
       if (typeof obj.length !== 'number' || isnan(obj.length)) {
-        return createBuffer(that, 0)
+        return createBuffer(0)
       }
-      return fromArrayLike(that, obj)
+      return fromArrayLike(obj)
     }
 
     if (obj.type === 'Buffer' && Array.isArray(obj.data)) {
-      return fromArrayLike(that, obj.data)
+      return fromArrayLike(obj.data)
     }
   }
 
@@ -1030,6 +1030,7 @@ Buffer.prototype.slice = function slice (start, end) {
   if (end < start) end = start
 
   var newBuf = this.subarray(start, end)
+  // Return an augmented `Uint8Array` instance
   newBuf.__proto__ = Buffer.prototype
   return newBuf
 }