From 54c5961ab13fbef46e030b711ac819f8ac32847a Mon Sep 17 00:00:00 2001
From: gwer <webholt@gmail.com>
Date: Tue, 28 Jan 2020 19:46:57 +0300
Subject: [PATCH 1/6] Reduce size by url generation and getRandomValues in loop

---
 async/index.browser.js | 29 +++++++++--------------------
 index.browser.js       | 28 ++++++++--------------------
 package.json           |  4 ++--
 3 files changed, 19 insertions(+), 42 deletions(-)

diff --git a/async/index.browser.js b/async/index.browser.js
index 68362643..abb1d016 100644
--- a/async/index.browser.js
+++ b/async/index.browser.js
@@ -7,36 +7,25 @@ var crypto = self.crypto || self.msCrypto
 // Despite the fact the source code is quite long, its entropy
 // is low and there are lots of duplicates - just what compressors
 // like GZIP and Brotli likes the best.
-var i
-var url = '_-' + String.fromCharCode(
-  // ASCII codes for 0...9
-  i = 48, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1,
-  i += 1, i += 1,
+var i = 36
+var url = '-_'
 
-  // ASCII codes for A...Z
-  i += 8, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1,
-  i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1,
-  i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1,
-  i += 1, i += 1,
-
-  // ASCII codes for a...z
-  i += 7, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1,
-  i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1,
-  i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1,
-  i += 1, i += 1
-)
+while (i--) {
+  url += i.toString(36)
+  i > 9 && (url += i.toString(36).toUpperCase())
+}
 
 module.exports = function (size) {
-  size = size || 21
   var id = ''
-  var bytes = crypto.getRandomValues(new Uint8Array(size))
+  size = size || 21
+
   // Compact alternative for `for (var i = 0; i < size; i++)`
   while (size--) {
     // We can’t use bytes bigger than the alphabet. 63 is 00111111 bitmask.
     // This mask reduces random byte 0-255 to 0-63 values.
     // There is no need in `|| ''` and `* 1.6` hacks in here,
     // because bitmask trim bytes exact to alphabet size.
-    id += url[bytes[size] & 63]
+    id += url[crypto.getRandomValues(new Uint8Array(1)) & 63]
   }
   return Promise.resolve(id)
 }
diff --git a/index.browser.js b/index.browser.js
index ea4e395f..3a02e3cb 100644
--- a/index.browser.js
+++ b/index.browser.js
@@ -24,36 +24,24 @@ var crypto = self.crypto || self.msCrypto
 // Despite the fact the source code is quite long, its entropy
 // is low and there are lots of duplicates - just what compressors
 // like GZIP and Brotli likes the best.
-var i
-var url = '_-' + String.fromCharCode(
-  // ASCII codes for 0...9
-  i = 48, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1,
-  i += 1, i += 1,
+var i = 36
+var url = '-_'
 
-  // ASCII codes for A...Z
-  i += 8, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1,
-  i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1,
-  i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1,
-  i += 1, i += 1,
-
-  // ASCII codes for a...z
-  i += 7, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1,
-  i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1,
-  i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1,
-  i += 1, i += 1
-)
+while (i--) {
+  url += i.toString(36)
+  i > 9 && (url += i.toString(36).toUpperCase())
+}
 
 module.exports = function (size) {
-  size = size || 21
   var id = ''
-  var bytes = crypto.getRandomValues(new Uint8Array(size))
+  size = size || 21
   // Compact alternative for `for (var i = 0; i < size; i++)`
   while (size--) {
     // We can’t use bytes bigger than the alphabet. 63 is 00111111 bitmask.
     // This mask reduces random byte 0-255 to 0-63 values.
     // There is no need in `|| ''` and `* 1.6` hacks in here,
     // because bitmask trim bytes exact to alphabet size.
-    id += url[bytes[size] & 63]
+    id += url[crypto.getRandomValues(new Uint8Array(1)) & 63]
   }
   return id
 }
diff --git a/package.json b/package.json
index c90d26e9..7d1cb509 100644
--- a/package.json
+++ b/package.json
@@ -66,7 +66,7 @@
   "size-limit": [
     {
       "path": "index.js",
-      "limit": "127 B"
+      "limit": "116 B"
     },
     {
       "path": "generate.js",
@@ -86,7 +86,7 @@
     },
     {
       "path": "async/index.js",
-      "limit": "139 B"
+      "limit": "126 B"
     },
     {
       "path": "async/generate.js",

From bd49e7ec2f6c319fbc98ce513d240d0207eab9ea Mon Sep 17 00:00:00 2001
From: gwer <webholt@gmail.com>
Date: Tue, 28 Jan 2020 20:46:23 +0300
Subject: [PATCH 2/6] Update non-secure index.js

---
 non-secure/index.js | 25 +++++++------------------
 package.json        |  2 +-
 2 files changed, 8 insertions(+), 19 deletions(-)

diff --git a/non-secure/index.js b/non-secure/index.js
index 08c4e319..1771a8e7 100644
--- a/non-secure/index.js
+++ b/non-secure/index.js
@@ -2,24 +2,13 @@
 // Despite the fact the source code is quite long, its entropy
 // is low and there are lots of duplicates - just what compressors
 // like GZIP and Brotli likes the best.
-var i
-var url = '_-' + String.fromCharCode(
-  // ASCII codes for 0...9
-  i = 48, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1,
-  i += 1, i += 1,
+var i = 36
+var url = '-_'
 
-  // ASCII codes for A...Z
-  i += 8, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1,
-  i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1,
-  i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1,
-  i += 1, i += 1,
-
-  // ASCII codes for a...z
-  i += 7, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1,
-  i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1,
-  i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1,
-  i += 1, i += 1
-)
+while (i--) {
+  url += i.toString(36)
+  i > 9 && (url += i.toString(36).toUpperCase())
+}
 
 /**
  * Generate URL-friendly unique ID. This method use non-secure predictable
@@ -37,8 +26,8 @@ var url = '_-' + String.fromCharCode(
  * @function
  */
 module.exports = function (size) {
-  size = size || 21
   var id = ''
+  size = size || 21
   // Compact alternative for `for (var i = 0; i < size; i++)`
   while (size--) {
     // `| 0` is compact and faster alternative for `Math.floor()`
diff --git a/package.json b/package.json
index 7d1cb509..ea88b75b 100644
--- a/package.json
+++ b/package.json
@@ -78,7 +78,7 @@
     },
     {
       "path": "non-secure/index.js",
-      "limit": "89 B"
+      "limit": "84 B"
     },
     {
       "path": "non-secure/generate.js",

From dbe155509b79d9645c668e70a357a428918a89e5 Mon Sep 17 00:00:00 2001
From: gwer <webholt@gmail.com>
Date: Tue, 28 Jan 2020 20:54:47 +0300
Subject: [PATCH 3/6] Update url.js

---
 url.js | 24 ++++++------------------
 1 file changed, 6 insertions(+), 18 deletions(-)

diff --git a/url.js b/url.js
index 5be82d1c..6a2a0dcd 100644
--- a/url.js
+++ b/url.js
@@ -3,8 +3,6 @@
 // is low and there are lots of duplicates - just what compressors
 // like GZIP and Brotli likes the best.
 
-var i
-
 /**
  * URL safe symbols.
  *
@@ -15,20 +13,10 @@ var i
  * const url = require('nanoid/url')
  * generate(url, 10) //=> "Uakgb_J5m9"
  */
-module.exports = '_-' + String.fromCharCode(
-  // ASCII codes for 0...9
-  i = 48, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1,
-  i += 1, i += 1,
-
-  // ASCII codes for A...Z
-  i += 8, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1,
-  i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1,
-  i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1,
-  i += 1, i += 1,
 
-  // ASCII codes for a...z
-  i += 7, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1,
-  i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1,
-  i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1, i += 1,
-  i += 1, i += 1
-)
+module.exports = '-_'
+var i = 36
+while (i--) {
+  module.exports += i.toString(36)
+  i > 9 && (module.exports += i.toString(36).toUpperCase())
+}

From df8ccf1c8c739347ba09240d54ff7672730bc040 Mon Sep 17 00:00:00 2001
From: gwer <webholt@gmail.com>
Date: Wed, 29 Jan 2020 09:51:09 +0300
Subject: [PATCH 4/6] Single call crypto.getRandomValues

---
 async/index.browser.js | 15 ++++++++++-----
 index.browser.js       | 16 +++++++++++-----
 non-secure/index.js    | 12 ++++++++----
 package.json           |  6 +++---
 4 files changed, 32 insertions(+), 17 deletions(-)

diff --git a/async/index.browser.js b/async/index.browser.js
index abb1d016..1ac42fae 100644
--- a/async/index.browser.js
+++ b/async/index.browser.js
@@ -7,25 +7,30 @@ var crypto = self.crypto || self.msCrypto
 // Despite the fact the source code is quite long, its entropy
 // is low and there are lots of duplicates - just what compressors
 // like GZIP and Brotli likes the best.
-var i = 36
 var url = '-_'
 
+var i = 36
 while (i--) {
   url += i.toString(36)
-  i > 9 && (url += i.toString(36).toUpperCase())
+}
+
+i = 36
+while (i-- - 10) {
+  url += i.toString(36).toUpperCase()
 }
 
 module.exports = function (size) {
   var id = ''
-  size = size || 21
+  var bytes = crypto.getRandomValues(new Uint8Array(size || 21))
+  i = size || 21
 
   // Compact alternative for `for (var i = 0; i < size; i++)`
-  while (size--) {
+  while (i--) {
     // We can’t use bytes bigger than the alphabet. 63 is 00111111 bitmask.
     // This mask reduces random byte 0-255 to 0-63 values.
     // There is no need in `|| ''` and `* 1.6` hacks in here,
     // because bitmask trim bytes exact to alphabet size.
-    id += url[crypto.getRandomValues(new Uint8Array(1)) & 63]
+    id += url[bytes[i] & 63]
   }
   return Promise.resolve(id)
 }
diff --git a/index.browser.js b/index.browser.js
index 3a02e3cb..0310066f 100644
--- a/index.browser.js
+++ b/index.browser.js
@@ -24,24 +24,30 @@ var crypto = self.crypto || self.msCrypto
 // Despite the fact the source code is quite long, its entropy
 // is low and there are lots of duplicates - just what compressors
 // like GZIP and Brotli likes the best.
-var i = 36
 var url = '-_'
 
+var i = 36
 while (i--) {
   url += i.toString(36)
-  i > 9 && (url += i.toString(36).toUpperCase())
+}
+
+i = 36
+while (i-- - 10) {
+  url += i.toString(36).toUpperCase()
 }
 
 module.exports = function (size) {
   var id = ''
-  size = size || 21
+  var bytes = crypto.getRandomValues(new Uint8Array(size || 21))
+  i = size || 21
+
   // Compact alternative for `for (var i = 0; i < size; i++)`
-  while (size--) {
+  while (i--) {
     // We can’t use bytes bigger than the alphabet. 63 is 00111111 bitmask.
     // This mask reduces random byte 0-255 to 0-63 values.
     // There is no need in `|| ''` and `* 1.6` hacks in here,
     // because bitmask trim bytes exact to alphabet size.
-    id += url[crypto.getRandomValues(new Uint8Array(1)) & 63]
+    id += url[bytes[i] & 63]
   }
   return id
 }
diff --git a/non-secure/index.js b/non-secure/index.js
index 1771a8e7..53081482 100644
--- a/non-secure/index.js
+++ b/non-secure/index.js
@@ -2,12 +2,16 @@
 // Despite the fact the source code is quite long, its entropy
 // is low and there are lots of duplicates - just what compressors
 // like GZIP and Brotli likes the best.
-var i = 36
 var url = '-_'
 
+var i = 36
 while (i--) {
   url += i.toString(36)
-  i > 9 && (url += i.toString(36).toUpperCase())
+}
+
+i = 36
+while (i-- - 10) {
+  url += i.toString(36).toUpperCase()
 }
 
 /**
@@ -27,9 +31,9 @@ while (i--) {
  */
 module.exports = function (size) {
   var id = ''
-  size = size || 21
+  i = size || 21
   // Compact alternative for `for (var i = 0; i < size; i++)`
-  while (size--) {
+  while (i--) {
     // `| 0` is compact and faster alternative for `Math.floor()`
     id += url[Math.random() * 64 | 0]
   }
diff --git a/package.json b/package.json
index ea88b75b..2e3f8619 100644
--- a/package.json
+++ b/package.json
@@ -66,7 +66,7 @@
   "size-limit": [
     {
       "path": "index.js",
-      "limit": "116 B"
+      "limit": "119 B"
     },
     {
       "path": "generate.js",
@@ -78,7 +78,7 @@
     },
     {
       "path": "non-secure/index.js",
-      "limit": "84 B"
+      "limit": "82 B"
     },
     {
       "path": "non-secure/generate.js",
@@ -86,7 +86,7 @@
     },
     {
       "path": "async/index.js",
-      "limit": "126 B"
+      "limit": "130 B"
     },
     {
       "path": "async/generate.js",

From 1d7ef8baa1c90685b40612da7b1259543303a489 Mon Sep 17 00:00:00 2001
From: gwer <webholt@gmail.com>
Date: Wed, 29 Jan 2020 10:43:55 +0300
Subject: [PATCH 5/6] Update comments

---
 async/index.browser.js | 11 ++++++++---
 index.browser.js       | 11 ++++++++---
 non-secure/index.js    | 11 ++++++++---
 url.js                 |  4 ++++
 4 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/async/index.browser.js b/async/index.browser.js
index 1ac42fae..a58bc209 100644
--- a/async/index.browser.js
+++ b/async/index.browser.js
@@ -4,17 +4,22 @@
 var crypto = self.crypto || self.msCrypto
 
 // This alphabet uses a-z A-Z 0-9 _- symbols.
-// Despite the fact the source code is quite long, its entropy
-// is low and there are lots of duplicates - just what compressors
-// like GZIP and Brotli likes the best.
+// Symbols are generated for better gzip compression.
+// Final url is
+// '-_zyxwvutsrqponmlkjihgfedcba9876543210ZYXWVUTSRQPONMLKJIHGFEDCBA'
 var url = '-_'
 
 var i = 36
 while (i--) {
+  // 36 is radix.
+  // Number.prototype.toString(36) returns number in Base36 representation
+  // Base36 is like hex,
+  // but Base36 is represented using the numerals 0–9 and the Latin letters A–Z
   url += i.toString(36)
 }
 
 i = 36
+// Loop from 36 to 10 (from Z to A in Base36)
 while (i-- - 10) {
   url += i.toString(36).toUpperCase()
 }
diff --git a/index.browser.js b/index.browser.js
index 0310066f..8a3fac1b 100644
--- a/index.browser.js
+++ b/index.browser.js
@@ -21,17 +21,22 @@ if (process.env.NODE_ENV !== 'production') {
 var crypto = self.crypto || self.msCrypto
 
 // This alphabet uses a-z A-Z 0-9 _- symbols.
-// Despite the fact the source code is quite long, its entropy
-// is low and there are lots of duplicates - just what compressors
-// like GZIP and Brotli likes the best.
+// Symbols are generated for better gzip compression.
+// Final url is
+// '-_zyxwvutsrqponmlkjihgfedcba9876543210ZYXWVUTSRQPONMLKJIHGFEDCBA'
 var url = '-_'
 
 var i = 36
 while (i--) {
+  // 36 is radix.
+  // Number.prototype.toString(36) returns number in Base36 representation
+  // Base36 is like hex,
+  // but Base36 is represented using the numerals 0–9 and the Latin letters A–Z
   url += i.toString(36)
 }
 
 i = 36
+// Loop from 36 to 10 (from Z to A in Base36)
 while (i-- - 10) {
   url += i.toString(36).toUpperCase()
 }
diff --git a/non-secure/index.js b/non-secure/index.js
index 53081482..b57dd893 100644
--- a/non-secure/index.js
+++ b/non-secure/index.js
@@ -1,15 +1,20 @@
 // This alphabet uses a-z A-Z 0-9 _- symbols.
-// Despite the fact the source code is quite long, its entropy
-// is low and there are lots of duplicates - just what compressors
-// like GZIP and Brotli likes the best.
+// Symbols are generated for better gzip compression.
+// Final url is
+// '-_zyxwvutsrqponmlkjihgfedcba9876543210ZYXWVUTSRQPONMLKJIHGFEDCBA'
 var url = '-_'
 
 var i = 36
 while (i--) {
+  // 36 is radix.
+  // Number.prototype.toString(36) returns number in Base36 representation
+  // Base36 is like hex,
+  // but Base36 is represented using the numerals 0–9 and the Latin letters A–Z
   url += i.toString(36)
 }
 
 i = 36
+// Loop from 36 to 10 (from Z to A in Base36)
 while (i-- - 10) {
   url += i.toString(36).toUpperCase()
 }
diff --git a/url.js b/url.js
index 6a2a0dcd..d567de25 100644
--- a/url.js
+++ b/url.js
@@ -17,6 +17,10 @@
 module.exports = '-_'
 var i = 36
 while (i--) {
+  // 36 is radix.
+  // Number.prototype.toString(36) returns number in Base36 representation
+  // Base36 is like hex,
+  // but Base36 is represented using the numerals 0–9 and the Latin letters A–Z
   module.exports += i.toString(36)
   i > 9 && (module.exports += i.toString(36).toUpperCase())
 }

From 6c6c0c6db3564139029034cf396c4636c21121c7 Mon Sep 17 00:00:00 2001
From: gwer <webholt@gmail.com>
Date: Wed, 29 Jan 2020 10:57:04 +0300
Subject: [PATCH 6/6] A-Z => a-z

---
 async/index.browser.js | 4 ++--
 index.browser.js       | 4 ++--
 non-secure/index.js    | 4 ++--
 url.js                 | 4 ++--
 4 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/async/index.browser.js b/async/index.browser.js
index a58bc209..2ead6973 100644
--- a/async/index.browser.js
+++ b/async/index.browser.js
@@ -12,9 +12,9 @@ var url = '-_'
 var i = 36
 while (i--) {
   // 36 is radix.
-  // Number.prototype.toString(36) returns number in Base36 representation
+  // Number.prototype.toString(36) returns number in Base36 representation.
   // Base36 is like hex,
-  // but Base36 is represented using the numerals 0–9 and the Latin letters A–Z
+  // but Base36 is represented using the numerals 0–9 and the Latin letters a-z
   url += i.toString(36)
 }
 
diff --git a/index.browser.js b/index.browser.js
index 8a3fac1b..2f5e2f65 100644
--- a/index.browser.js
+++ b/index.browser.js
@@ -29,9 +29,9 @@ var url = '-_'
 var i = 36
 while (i--) {
   // 36 is radix.
-  // Number.prototype.toString(36) returns number in Base36 representation
+  // Number.prototype.toString(36) returns number in Base36 representation.
   // Base36 is like hex,
-  // but Base36 is represented using the numerals 0–9 and the Latin letters A–Z
+  // but Base36 is represented using the numerals 0–9 and the Latin letters a-z
   url += i.toString(36)
 }
 
diff --git a/non-secure/index.js b/non-secure/index.js
index b57dd893..94f0cbd9 100644
--- a/non-secure/index.js
+++ b/non-secure/index.js
@@ -7,9 +7,9 @@ var url = '-_'
 var i = 36
 while (i--) {
   // 36 is radix.
-  // Number.prototype.toString(36) returns number in Base36 representation
+  // Number.prototype.toString(36) returns number in Base36 representation.
   // Base36 is like hex,
-  // but Base36 is represented using the numerals 0–9 and the Latin letters A–Z
+  // but Base36 is represented using the numerals 0–9 and the Latin letters a-z
   url += i.toString(36)
 }
 
diff --git a/url.js b/url.js
index d567de25..cf95ea4d 100644
--- a/url.js
+++ b/url.js
@@ -18,9 +18,9 @@ module.exports = '-_'
 var i = 36
 while (i--) {
   // 36 is radix.
-  // Number.prototype.toString(36) returns number in Base36 representation
+  // Number.prototype.toString(36) returns number in Base36 representation.
   // Base36 is like hex,
-  // but Base36 is represented using the numerals 0–9 and the Latin letters A–Z
+  // but Base36 is represented using the numerals 0–9 and the Latin letters a-z
   module.exports += i.toString(36)
   i > 9 && (module.exports += i.toString(36).toUpperCase())
 }