diff --git a/README.md b/README.md
index 6bdef26..f0aeda7 100644
--- a/README.md
+++ b/README.md
@@ -13,15 +13,15 @@ when using [the Buffer implementation provided by Browserify](https://www.npmjs.
 ## Usage
 
 ``` js
-var toArrayBuffer = require('to-arraybuffer')
+import toArrayBuffer from 'to-arraybuffer'
 
-var buffer = new Buffer(100)
+const buffer = Buffer.alloc(100)
 // Fill the buffer with some data
 
-var ab = toArrayBuffer(buffer)
+const ab = toArrayBuffer(buffer)
 // `ab` now contains the same data as `buffer`
 ```
 
 ## License
 
-MIT
\ No newline at end of file
+MIT
diff --git a/index.js b/index.js
index 2f69ae0..55d2cef 100644
--- a/index.js
+++ b/index.js
@@ -1,27 +1,12 @@
-var Buffer = require('buffer').Buffer
+/** @param {ArrayBufferView} buf */
+module.exports = buf => {
+  if (buf instanceof ArrayBuffer) return buf
 
-module.exports = function (buf) {
-	// If the buffer is backed by a Uint8Array, a faster version will work
-	if (buf instanceof Uint8Array) {
-		// If the buffer isn't a subarray, return the underlying ArrayBuffer
-		if (buf.byteOffset === 0 && buf.byteLength === buf.buffer.byteLength) {
-			return buf.buffer
-		} else if (typeof buf.buffer.slice === 'function') {
-			// Otherwise we need to get a proper copy
-			return buf.buffer.slice(buf.byteOffset, buf.byteOffset + buf.byteLength)
-		}
-	}
+  if (!ArrayBuffer.isView(buf)) throw new Error('Argument must be a ArrayBufferView')
 
-	if (Buffer.isBuffer(buf)) {
-		// This is the slow version that will work with any Buffer
-		// implementation (even in old browsers)
-		var arrayCopy = new Uint8Array(buf.length)
-		var len = buf.length
-		for (var i = 0; i < len; i++) {
-			arrayCopy[i] = buf[i]
-		}
-		return arrayCopy.buffer
-	} else {
-		throw new Error('Argument must be a Buffer')
-	}
+  // If the buffer isn't a subarray, return the underlying ArrayBuffer
+  // Otherwise we need to get a proper copy
+  return buf.byteLength === buf.buffer.byteLength
+    ? buf.buffer
+    : buf.buffer.slice(buf.byteOffset, buf.byteOffset + buf.byteLength)
 }
diff --git a/package.json b/package.json
index 9ed4674..0aee88f 100644
--- a/package.json
+++ b/package.json
@@ -9,6 +9,9 @@
     "test-browser": "airtap --loopback airtap.local -- test.js",
     "test-browser-local": "airtap --no-instrument --local 8080 -- test.js"
   },
+  "files": [
+    "index.js"
+  ],
   "repository": {
     "type": "git",
     "url": "git://github.com/jhiesey/to-arraybuffer.git"
@@ -28,7 +31,7 @@
   },
   "homepage": "https://github.com/jhiesey/to-arraybuffer#readme",
   "devDependencies": {
-    "airtap": "^0.0.5",
-    "tape": "^4.9.0"
+    "airtap": "^3.0.0",
+    "tape": "^5.2.2"
   }
 }
diff --git a/test.js b/test.js
index 1814ae3..6235a8c 100644
--- a/test.js
+++ b/test.js
@@ -1,57 +1,57 @@
-var Buffer = require('buffer').Buffer
-var test = require('tape')
+const { Buffer } = require('buffer')
+const test = require('tape')
 
-var toArrayBuffer = require('.')
+const toArrayBuffer = require('./index.js')
 
 function elementsEqual (ab, buffer) {
-	var view = new Uint8Array(ab)
-	for (var i = 0; i < view.length; i++) {
-		if (view[i] !== buffer[i]) {
-			return false
-		}
-	}
-	return true
+  const view = new Uint8Array(ab)
+  for (let i = 0; i < view.length; i++) {
+    if (view[i] !== buffer[i]) {
+      return false
+    }
+  }
+  return true
 }
 
 test('Basic behavior', function (t) {
-	var buf = new Buffer(10)
-	for (var i = 0; i < 10; i++) {
-		buf[i] = i
-	}
+  const buf = Buffer.alloc(10)
+  for (let i = 0; i < 10; i++) {
+    buf[i] = i
+  }
 
-	var ab = toArrayBuffer(buf)
+  const ab = toArrayBuffer(buf)
 
-	t.equals(ab.byteLength, 10, 'correct length')
-	t.ok(elementsEqual(ab, buf), 'elements equal')
-	t.end()
+  t.equals(ab.byteLength, 10, 'correct length')
+  t.ok(elementsEqual(ab, buf), 'elements equal')
+  t.end()
 })
 
 test('Behavior when input is a subarray 1', function (t) {
-	var origBuf = new Buffer(10)
-	for (var i = 0; i < 10; i++) {
-		origBuf[i] = i
-	}
-	var buf = origBuf.slice(1)
-
-	var ab = toArrayBuffer(buf)
-
-	t.equals(ab.byteLength, 9, 'correct length')
-	t.ok(elementsEqual(ab, buf), 'elements equal')
-	t.notOk(ab === buf.buffer, 'the underlying ArrayBuffer is not returned when incorrect')
-	t.end()
+  const origBuf = Buffer.alloc(10)
+  for (let i = 0; i < 10; i++) {
+    origBuf[i] = i
+  }
+  const buf = origBuf.slice(1)
+
+  const ab = toArrayBuffer(buf)
+
+  t.equals(ab.byteLength, 9, 'correct length')
+  t.ok(elementsEqual(ab, buf), 'elements equal')
+  t.notOk(ab === buf.buffer, 'the underlying ArrayBuffer is not returned when incorrect')
+  t.end()
 })
 
 test('Behavior when input is a subarray 2', function (t) {
-	var origBuf = new Buffer(10)
-	for (var i = 0; i < 10; i++) {
-		origBuf[i] = i
-	}
-	var buf = origBuf.slice(0, 9)
-
-	var ab = toArrayBuffer(buf)
-
-	t.equals(ab.byteLength, 9, 'correct length')
-	t.ok(elementsEqual(ab, buf), 'elements equal')
-	t.notOk(ab === buf.buffer, 'the underlying ArrayBuffer is not returned when incorrect')
-	t.end()
+  const origBuf = Buffer.alloc(10)
+  for (let i = 0; i < 10; i++) {
+    origBuf[i] = i
+  }
+  const buf = origBuf.slice(0, 9)
+
+  const ab = toArrayBuffer(buf)
+
+  t.equals(ab.byteLength, 9, 'correct length')
+  t.ok(elementsEqual(ab, buf), 'elements equal')
+  t.notOk(ab === buf.buffer, 'the underlying ArrayBuffer is not returned when incorrect')
+  t.end()
 })