From 2db8cf025a74046d48a82caacd195ef04e72d7c7 Mon Sep 17 00:00:00 2001
From: awwit <ignatius.awwit@gmail.com>
Date: Tue, 5 May 2020 17:35:13 +0300
Subject: [PATCH 1/4] feat: improved v4 performance

---
 src/rng.js |  4 +++-
 src/v4.js  | 12 +++++++-----
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/src/rng.js b/src/rng.js
index 33513bb8..53e5bcd9 100644
--- a/src/rng.js
+++ b/src/rng.js
@@ -1,5 +1,7 @@
 import crypto from 'crypto';
 
+const rnds8 = new Uint8Array(16);
+
 export default function rng() {
-  return crypto.randomBytes(16);
+  return crypto.randomFillSync(rnds8);
 }
diff --git a/src/v4.js b/src/v4.js
index 63daa5a4..e252b0db 100644
--- a/src/v4.js
+++ b/src/v4.js
@@ -2,10 +2,10 @@ import rng from './rng.js';
 import bytesToUuid from './bytesToUuid.js';
 
 function v4(options, buf, offset) {
-  const i = (buf && offset) || 0;
+  const start = (buf && offset) || 0;
 
   if (typeof options === 'string') {
-    buf = options === 'binary' ? new Uint32Array(16) : null;
+    buf = options === 'binary' ? new Uint8Array(16) : null;
     options = null;
   }
 
@@ -19,12 +19,14 @@ function v4(options, buf, offset) {
 
   // Copy bytes to buffer, if provided
   if (buf) {
-    for (let ii = 0; ii < 16; ++ii) {
-      buf[i + ii] = rnds[ii];
+    for (let i = 0; i < 16; ++i) {
+      buf[start + i] = rnds[i];
     }
+
+    return buf;
   }
 
-  return buf || bytesToUuid(rnds);
+  return bytesToUuid(rnds);
 }
 
 export default v4;

From 475f831d0a22b9f76a5d6d8f7a177ec5bfeff8e8 Mon Sep 17 00:00:00 2001
From: awwit <ignatius.awwit@gmail.com>
Date: Tue, 5 May 2020 17:49:23 +0300
Subject: [PATCH 2/4] test: fix for docs:diff

---
 README_js.md | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/README_js.md b/README_js.md
index e20f6580..2eb1a7e4 100644
--- a/README_js.md
+++ b/README_js.md
@@ -8,9 +8,8 @@ runmd.onRequire = (path) => {
 runmd.Date.now = () => 1551914748172;
 
 let seed = 0xdefaced;
-require('crypto').randomBytes = function () {
-  const a = [];
-  for (let i = 0; i < 16; i++) a.push((seed = (seed * 0x41a7) & 0x7fffffff) & 0xff);
+require('crypto').randomFillSync = function (a) {
+  for (let i = 0; i < 16; i++) a[i] = (seed = (seed * 0x41a7) & 0x7fffffff) & 0xff;
   return a;
 };
 ```

From 13ac37dad7afe58ea67b5abc7848aca55a850671 Mon Sep 17 00:00:00 2001
From: awwit <ignatius.awwit@gmail.com>
Date: Wed, 6 May 2020 23:47:41 +0300
Subject: [PATCH 3/4] feat: moved offset init in v4

---
 src/v4.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/v4.js b/src/v4.js
index e252b0db..44bfa947 100644
--- a/src/v4.js
+++ b/src/v4.js
@@ -2,8 +2,6 @@ import rng from './rng.js';
 import bytesToUuid from './bytesToUuid.js';
 
 function v4(options, buf, offset) {
-  const start = (buf && offset) || 0;
-
   if (typeof options === 'string') {
     buf = options === 'binary' ? new Uint8Array(16) : null;
     options = null;
@@ -19,6 +17,8 @@ function v4(options, buf, offset) {
 
   // Copy bytes to buffer, if provided
   if (buf) {
+    const start = offset || 0;
+
     for (let i = 0; i < 16; ++i) {
       buf[start + i] = rnds[i];
     }

From f79caf0c098b05cdaf8acb0a1bcc8139882cfa8b Mon Sep 17 00:00:00 2001
From: awwit <ignatius.awwit@gmail.com>
Date: Wed, 6 May 2020 23:49:35 +0300
Subject: [PATCH 4/4] test: v4 result with buf arg

---
 test/unit/v4.test.js | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/test/unit/v4.test.js b/test/unit/v4.test.js
index d18f7ea5..6275dd40 100644
--- a/test/unit/v4.test.js
+++ b/test/unit/v4.test.js
@@ -45,13 +45,14 @@ describe('v4', () => {
 
   test('fills one UUID into a buffer as expected', () => {
     const buffer = [];
-    v4(
+    const result = v4(
       {
         random: randomBytesFixture,
       },
       buffer,
     );
     assert.deepEqual(buffer, expectedBytes);
+    assert.strictEqual(buffer, result);
   });
 
   test('fills two UUIDs into a buffer as expected', () => {