From f723253f784ef4f0dab782e04dc18e62ee4df65d Mon Sep 17 00:00:00 2001
From: joaquinelio <joaquinelio@gmail.com>
Date: Sun, 28 Mar 2021 00:08:17 -0300
Subject: [PATCH 01/26] transpiler def

---
 1-js/03-code-quality/06-polyfills/article.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/1-js/03-code-quality/06-polyfills/article.md b/1-js/03-code-quality/06-polyfills/article.md
index af38faad2..9d119132e 100644
--- a/1-js/03-code-quality/06-polyfills/article.md
+++ b/1-js/03-code-quality/06-polyfills/article.md
@@ -22,7 +22,7 @@ Here, in this chapter, our purpose is to get the gist of how they work, and thei
 
 ## Transpilers
 
-A [transpiler](https://en.wikipedia.org/wiki/Source-to-source_compiler) is a special piece of software that can parse ("read and understand") modern code, and rewrite it using older syntax constructs, so that the result would be the same.
+A [transpiler](https://en.wikipedia.org/wiki/Source-to-source_compiler) is a special piece of software that can parse ("read and understand") modern code, and rewrite it using syntax constructs that the target engine (even oudated ones) can run.
 
 E.g. JavaScript before year 2020 didn't have the "nullish coalescing operator" `??`. So, if a visitor uses an outdated browser, it may fail to understand the code like `height = height ?? 100`.
 

From 3d88d3322e97c06c3cbd09bb58f6a025351130a6 Mon Sep 17 00:00:00 2001
From: Z Yin <z.yin.md@gmail.com>
Date: Sun, 13 Jun 2021 16:48:40 -0400
Subject: [PATCH 02/26] Update article.md

---
 1-js/05-data-types/02-number/article.md | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/1-js/05-data-types/02-number/article.md b/1-js/05-data-types/02-number/article.md
index 6fd513f43..6f9ddd953 100644
--- a/1-js/05-data-types/02-number/article.md
+++ b/1-js/05-data-types/02-number/article.md
@@ -37,8 +37,8 @@ alert( 7.3e9 );  // 7.3 billions (same as 7300000000 or 7_300_000_000)
 In other words, `e` multiplies the number by `1` with the given zeroes count.
 
 ```js
-1e3 = 1 * 1000 // e3 means *1000
-1.23e6 = 1.23 * 1000000 // e6 means *1000000
+1e3 === 1 * 1000; // e3 means *1000
+1.23e6 === 1.23 * 1000000; // e6 means *1000000
 ```
 
 Now let's write something very small. Say, 1 microsecond (one millionth of a second):
@@ -59,10 +59,10 @@ In other words, a negative number after `"e"` means a division by 1 with the giv
 
 ```js
 // -3 divides by 1 with 3 zeroes
-1e-3 = 1 / 1000 (=0.001)
+1e-3 === 1 / 1000; // 0.001
 
 // -6 divides by 1 with 6 zeroes
-1.23e-6 = 1.23 / 1000000 (=0.00000123)
+1.23e-6 === 1.23 / 1000000; // 0.00000123
 ```
 
 ### Hex, binary and octal numbers
@@ -118,6 +118,7 @@ Please note that two dots in `123456..toString(36)` is not a typo. If we want to
 If we placed a single dot: `123456.toString(36)`, then there would be an error, because JavaScript syntax implies the decimal part after the first dot. And if we place one more dot, then JavaScript knows that the decimal part is empty and now goes the method.
 
 Also could write `(123456).toString(36)`.
+
 ```
 
 ## Rounding

From 2dce19e3e9bc37d2e473e137157ab48c99340676 Mon Sep 17 00:00:00 2001
From: joaquinelio <joaquinelio@gmail.com>
Date: Wed, 16 Jun 2021 02:05:38 -0300
Subject: [PATCH 03/26] "inserts into" instead of "appends to"

---
 1-js/11-async/01-callbacks/article.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/1-js/11-async/01-callbacks/article.md b/1-js/11-async/01-callbacks/article.md
index 344d92b74..9432e860b 100644
--- a/1-js/11-async/01-callbacks/article.md
+++ b/1-js/11-async/01-callbacks/article.md
@@ -28,7 +28,7 @@ function loadScript(src) {
 }
 ```
 
-It appends to the document the new, dynamically created, tag `<script src="…">` with given `src`. The browser automatically starts loading it and executes when complete.
+It inserts into the document the new, dynamically created, tag `<script src="…">` with the given `src`. The browser automatically starts loading it and executes when complete.
 
 We can use this function like this:
 

From 497ca99529c72bbf19b45cdae590899b6f283a87 Mon Sep 17 00:00:00 2001
From: joaquinelio <joaquinelio@gmail.com>
Date: Wed, 16 Jun 2021 08:32:53 -0300
Subject: [PATCH 04/26] Update article.md

---
 1-js/11-async/01-callbacks/article.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/1-js/11-async/01-callbacks/article.md b/1-js/11-async/01-callbacks/article.md
index 9432e860b..8f9189ae3 100644
--- a/1-js/11-async/01-callbacks/article.md
+++ b/1-js/11-async/01-callbacks/article.md
@@ -28,7 +28,7 @@ function loadScript(src) {
 }
 ```
 
-It inserts into the document the new, dynamically created, tag `<script src="…">` with the given `src`. The browser automatically starts loading it and executes when complete.
+It inserts into the document a new, dynamically created, tag `<script src="…">` with the given `src`. The browser automatically starts loading it and executes when complete.
 
 We can use this function like this:
 

From cd466c514aa10e16fbf3166fc1db1240afc92905 Mon Sep 17 00:00:00 2001
From: Rohan Rawat <rohan.rawat.9897@gmail.com>
Date: Fri, 18 Jun 2021 01:54:25 +0530
Subject: [PATCH 05/26] Unnecessary escape characters in cookie.js

Removed unnecessary escape characters from regex in "getCookie function in cookie.js" -
. ( ) [ / +
The above characters don't need escaping.
---
 6-data-storage/01-cookie/cookie.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/6-data-storage/01-cookie/cookie.js b/6-data-storage/01-cookie/cookie.js
index cd3e17c02..653ea5b7f 100644
--- a/6-data-storage/01-cookie/cookie.js
+++ b/6-data-storage/01-cookie/cookie.js
@@ -1,6 +1,6 @@
 function getCookie(name) {
   let matches = document.cookie.match(new RegExp(
-    "(?:^|; )" + name.replace(/([\.$?*|{}\(\)\[\]\\\/\+^])/g, '\\$1') + "=([^;]*)"
+    "(?:^|; )" + name.replace(/([.$?*|{}()[\]\\/+^])/g, '\\$1') + "=([^;]*)"
   ));
   return matches ? decodeURIComponent(matches[1]) : undefined;
 }

From 8c910b4ace3e88580c96315920b198f175dc23a2 Mon Sep 17 00:00:00 2001
From: joaquinelio <joaquinelio@gmail.com>
Date: Fri, 18 Jun 2021 04:39:25 -0300
Subject: [PATCH 06/26] Update article.md

---
 1-js/03-code-quality/06-polyfills/article.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/1-js/03-code-quality/06-polyfills/article.md b/1-js/03-code-quality/06-polyfills/article.md
index 9d119132e..a10391768 100644
--- a/1-js/03-code-quality/06-polyfills/article.md
+++ b/1-js/03-code-quality/06-polyfills/article.md
@@ -22,7 +22,7 @@ Here, in this chapter, our purpose is to get the gist of how they work, and thei
 
 ## Transpilers
 
-A [transpiler](https://en.wikipedia.org/wiki/Source-to-source_compiler) is a special piece of software that can parse ("read and understand") modern code, and rewrite it using syntax constructs that the target engine (even oudated ones) can run.
+A [transpiler](https://en.wikipedia.org/wiki/Source-to-source_compiler) is a special piece of software that translates source code to another source code. It can to parse ("read and understand") modern code and rewrite it using older syntax constructs, so the result would be the same in both, modern and outdated engines.
 
 E.g. JavaScript before year 2020 didn't have the "nullish coalescing operator" `??`. So, if a visitor uses an outdated browser, it may fail to understand the code like `height = height ?? 100`.
 

From 8cf2d51e7de23da5ee4e015913b1ac54ffe3d812 Mon Sep 17 00:00:00 2001
From: joaquinelio <joaquinelio@gmail.com>
Date: Fri, 18 Jun 2021 04:40:04 -0300
Subject: [PATCH 07/26] Update article.md

---
 1-js/03-code-quality/06-polyfills/article.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/1-js/03-code-quality/06-polyfills/article.md b/1-js/03-code-quality/06-polyfills/article.md
index a10391768..515ecd95a 100644
--- a/1-js/03-code-quality/06-polyfills/article.md
+++ b/1-js/03-code-quality/06-polyfills/article.md
@@ -22,7 +22,7 @@ Here, in this chapter, our purpose is to get the gist of how they work, and thei
 
 ## Transpilers
 
-A [transpiler](https://en.wikipedia.org/wiki/Source-to-source_compiler) is a special piece of software that translates source code to another source code. It can to parse ("read and understand") modern code and rewrite it using older syntax constructs, so the result would be the same in both, modern and outdated engines.
+A [transpiler](https://en.wikipedia.org/wiki/Source-to-source_compiler) is a special piece of software that translates source code to another source code. It can parse ("read and understand") modern code and rewrite it using older syntax constructs, so the result would be the same in both, modern and outdated engines.
 
 E.g. JavaScript before year 2020 didn't have the "nullish coalescing operator" `??`. So, if a visitor uses an outdated browser, it may fail to understand the code like `height = height ?? 100`.
 

From 0c41930be9b35c9b0b0a99d1fb9e8d3070585eea Mon Sep 17 00:00:00 2001
From: joaquinelio <joaquinelio@gmail.com>
Date: Fri, 18 Jun 2021 05:57:45 -0300
Subject: [PATCH 08/26] Update article.md

---
 1-js/03-code-quality/06-polyfills/article.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/1-js/03-code-quality/06-polyfills/article.md b/1-js/03-code-quality/06-polyfills/article.md
index 515ecd95a..6baae668c 100644
--- a/1-js/03-code-quality/06-polyfills/article.md
+++ b/1-js/03-code-quality/06-polyfills/article.md
@@ -22,7 +22,7 @@ Here, in this chapter, our purpose is to get the gist of how they work, and thei
 
 ## Transpilers
 
-A [transpiler](https://en.wikipedia.org/wiki/Source-to-source_compiler) is a special piece of software that translates source code to another source code. It can parse ("read and understand") modern code and rewrite it using older syntax constructs, so the result would be the same in both, modern and outdated engines.
+A [transpiler](https://en.wikipedia.org/wiki/Source-to-source_compiler) is a special piece of software that translates source code to another source code. We use it here to parse ("read and understand") modern code and rewrite it using older syntax constructs, so the result would be the same in both, modern and outdated engines.
 
 E.g. JavaScript before year 2020 didn't have the "nullish coalescing operator" `??`. So, if a visitor uses an outdated browser, it may fail to understand the code like `height = height ?? 100`.
 

From 263f57ed41a3ebae30e64314469cf030aa5093c0 Mon Sep 17 00:00:00 2001
From: joaquinelio <joaquinelio@gmail.com>
Date: Fri, 18 Jun 2021 06:12:58 -0300
Subject: [PATCH 09/26] Update article.md

---
 1-js/03-code-quality/06-polyfills/article.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/1-js/03-code-quality/06-polyfills/article.md b/1-js/03-code-quality/06-polyfills/article.md
index 6baae668c..515ecd95a 100644
--- a/1-js/03-code-quality/06-polyfills/article.md
+++ b/1-js/03-code-quality/06-polyfills/article.md
@@ -22,7 +22,7 @@ Here, in this chapter, our purpose is to get the gist of how they work, and thei
 
 ## Transpilers
 
-A [transpiler](https://en.wikipedia.org/wiki/Source-to-source_compiler) is a special piece of software that translates source code to another source code. We use it here to parse ("read and understand") modern code and rewrite it using older syntax constructs, so the result would be the same in both, modern and outdated engines.
+A [transpiler](https://en.wikipedia.org/wiki/Source-to-source_compiler) is a special piece of software that translates source code to another source code. It can parse ("read and understand") modern code and rewrite it using older syntax constructs, so the result would be the same in both, modern and outdated engines.
 
 E.g. JavaScript before year 2020 didn't have the "nullish coalescing operator" `??`. So, if a visitor uses an outdated browser, it may fail to understand the code like `height = height ?? 100`.
 

From a6dfbb7574501052c53c26cee58b3508411f9f20 Mon Sep 17 00:00:00 2001
From: Ilya Kantor <iliakan@gmail.com>
Date: Fri, 18 Jun 2021 19:48:55 +0300
Subject: [PATCH 10/26] minor fixes

---
 1-js/03-code-quality/06-polyfills/article.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/1-js/03-code-quality/06-polyfills/article.md b/1-js/03-code-quality/06-polyfills/article.md
index ef431108e..02be20872 100644
--- a/1-js/03-code-quality/06-polyfills/article.md
+++ b/1-js/03-code-quality/06-polyfills/article.md
@@ -22,7 +22,7 @@ Here, in this chapter, our purpose is to get the gist of how they work, and thei
 
 ## Transpilers
 
-A [transpiler](https://en.wikipedia.org/wiki/Source-to-source_compiler) is a special piece of software that translates source code to another source code. It can parse ("read and understand") modern code and rewrite it using older syntax constructs, so the result would be the same in both, modern and outdated engines.
+A [transpiler](https://en.wikipedia.org/wiki/Source-to-source_compiler) is a special piece of software that translates source code to another source code. It can parse ("read and understand") modern code and rewrite it using older syntax constructs, so that it'll also work in outdated engines.
 
 E.g. JavaScript before year 2020 didn't have the "nullish coalescing operator" `??`. So, if a visitor uses an outdated browser, it may fail to understand the code like `height = height ?? 100`.
 

From de36d0dffbfa437df4e7109edb15e46cd68adb76 Mon Sep 17 00:00:00 2001
From: Z Yin <z.yin.md@gmail.com>
Date: Fri, 18 Jun 2021 13:18:05 -0400
Subject: [PATCH 11/26] update one code comment in
 1-js/09-classes/04-private-protected-properties-methods

It looks like code was changed some time ago, but comments didn't change accordingly.
---
 .../04-private-protected-properties-methods/article.md          | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/1-js/09-classes/04-private-protected-properties-methods/article.md b/1-js/09-classes/04-private-protected-properties-methods/article.md
index e26d0ec81..91efb89ee 100644
--- a/1-js/09-classes/04-private-protected-properties-methods/article.md
+++ b/1-js/09-classes/04-private-protected-properties-methods/article.md
@@ -116,7 +116,7 @@ class CoffeeMachine {
 let coffeeMachine = new CoffeeMachine(100);
 
 // add water
-coffeeMachine.waterAmount = -10; // Error: Negative water
+coffeeMachine.waterAmount = -10; // _waterAmount will become 0, not -10
 ```
 
 Now the access is under control, so setting the water amount below zero becomes impossible.

From c45e78fdff480fa2d2f8e0eb439a5ec88f92a781 Mon Sep 17 00:00:00 2001
From: joaquinelio <joaquinelio@gmail.com>
Date: Fri, 18 Jun 2021 18:09:05 -0300
Subject: [PATCH 12/26] Maybe. "accessors" link

---
 6-data-storage/01-cookie/article.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/6-data-storage/01-cookie/article.md b/6-data-storage/01-cookie/article.md
index ac2fda063..33161cd97 100644
--- a/6-data-storage/01-cookie/article.md
+++ b/6-data-storage/01-cookie/article.md
@@ -39,7 +39,7 @@ We leave it as an exercise for the reader. Also, at the end of the chapter you'l
 
 ## Writing to document.cookie
 
-We can write to `document.cookie`. But it's not a data property, it's an accessor (getter/setter). An assignment to it is treated specially.
+We can write to `document.cookie`. But it's not a data property, it's an [accessor (getter/setter)](info:property-accessors). An assignment to it is treated specially.
 
 **A write operation to `document.cookie` updates only cookies mentioned in it, but doesn't touch other cookies.**
 

From d43bdd28ebd2163d15bf2b353a3720fb061cef52 Mon Sep 17 00:00:00 2001
From: Z Yin <z.yin.md@gmail.com>
Date: Fri, 18 Jun 2021 23:37:39 -0400
Subject: [PATCH 13/26] slightly improve clarity on Promise.all()

---
 1-js/11-async/05-promise-api/article.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/1-js/11-async/05-promise-api/article.md b/1-js/11-async/05-promise-api/article.md
index 2375f1e74..9e97b1e5b 100644
--- a/1-js/11-async/05-promise-api/article.md
+++ b/1-js/11-async/05-promise-api/article.md
@@ -18,7 +18,7 @@ let promise = Promise.all([...promises...]);
 
 `Promise.all` takes an array of promises (it technically can be any iterable, but is usually an array) and returns a new promise.
 
-The new promise resolves when all listed promises are settled, and the array of their results becomes its result.
+The new promise resolves when all listed promises are resolved, and the array of their results becomes its result.
 
 For instance, the `Promise.all` below settles after 3 seconds, and then its result is an array `[1, 2, 3]`:
 

From e8777963b2a7648b5dc82d7430901d7f9e57cb90 Mon Sep 17 00:00:00 2001
From: Ilya Kantor <iliakan@gmail.com>
Date: Sat, 19 Jun 2021 18:44:32 +0300
Subject: [PATCH 14/26] closes #2641

---
 2-ui/3-event-details/7-keyboard-events/article.md | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/2-ui/3-event-details/7-keyboard-events/article.md b/2-ui/3-event-details/7-keyboard-events/article.md
index 54bde42b4..b4b398062 100644
--- a/2-ui/3-event-details/7-keyboard-events/article.md
+++ b/2-ui/3-event-details/7-keyboard-events/article.md
@@ -139,12 +139,16 @@ For instance, the `<input>` below expects a phone number, so it does not accept
 ```html autorun height=60 run
 <script>
 function checkPhoneKey(key) {
-  return (key >= '0' && key <= '9') || key == '+' || key == '(' || key == ')' || key == '-';
+  return (key >= '0' && key <= '9') || ['+','(',')','-'].includes(key);
 }
 </script>
 <input *!*onkeydown="return checkPhoneKey(event.key)"*/!* placeholder="Phone, please" type="tel">
 ```
 
+The `onkeydown` handler here uses `checkPhoneKey` to check for the key pressed. If it's valid (from `0..9` or one of `+-()`), then it returns `true`, otherwise `false`.
+
+As we know, the `false` value returned from the event handler, assigned using a DOM property or an attribute, such as above, prevents the default action, so nothing appears in the `<input>` for keys that don't pass the test. (The `true` value returned doesn't affect anything, only returning `false` matters)
+
 Please note that special keys, such as `key:Backspace`, `key:Left`, `key:Right`, `key:Ctrl+V`, do not work in the input. That's a side-effect of the strict filter `checkPhoneKey`.
 
 Let's relax it a little bit:
@@ -153,8 +157,8 @@ Let's relax it a little bit:
 ```html autorun height=60 run
 <script>
 function checkPhoneKey(key) {
-  return (key >= '0' && key <= '9') || key == '+' || key == '(' || key == ')' || key == '-' ||
-    key == 'ArrowLeft' || key == 'ArrowRight' || key == 'Delete' || key == 'Backspace';
+  return (key >= '0' && key <= '9') ||
+    ['+','(',')','-','ArrowLeft','ArrowRight','Delete','Backspace'].includes(key);
 }
 </script>
 <input onkeydown="return checkPhoneKey(event.key)" placeholder="Phone, please" type="tel">

From ff53f0638b4fcf9a4ab851b175d28d32a465f42f Mon Sep 17 00:00:00 2001
From: Ilya Kantor <iliakan@gmail.com>
Date: Sat, 19 Jun 2021 18:48:57 +0300
Subject: [PATCH 15/26] minor fixes

---
 2-ui/3-event-details/7-keyboard-events/article.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/2-ui/3-event-details/7-keyboard-events/article.md b/2-ui/3-event-details/7-keyboard-events/article.md
index b4b398062..d7892b683 100644
--- a/2-ui/3-event-details/7-keyboard-events/article.md
+++ b/2-ui/3-event-details/7-keyboard-events/article.md
@@ -151,7 +151,7 @@ As we know, the `false` value returned from the event handler, assigned using a
 
 Please note that special keys, such as `key:Backspace`, `key:Left`, `key:Right`, `key:Ctrl+V`, do not work in the input. That's a side-effect of the strict filter `checkPhoneKey`.
 
-Let's relax it a little bit:
+Let's relax it a little bit by allowing `key:Left`, `key:Right` arrows and `key:Delete`, `key:Backspace`:
 
 
 ```html autorun height=60 run

From cf82cc3bcedc08eeb545a9caf7a246170d23d6c6 Mon Sep 17 00:00:00 2001
From: Ilya Kantor <iliakan@gmail.com>
Date: Sat, 19 Jun 2021 18:49:46 +0300
Subject: [PATCH 16/26] minor fixes

---
 2-ui/3-event-details/7-keyboard-events/article.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/2-ui/3-event-details/7-keyboard-events/article.md b/2-ui/3-event-details/7-keyboard-events/article.md
index d7892b683..6318fde21 100644
--- a/2-ui/3-event-details/7-keyboard-events/article.md
+++ b/2-ui/3-event-details/7-keyboard-events/article.md
@@ -149,7 +149,7 @@ The `onkeydown` handler here uses `checkPhoneKey` to check for the key pressed.
 
 As we know, the `false` value returned from the event handler, assigned using a DOM property or an attribute, such as above, prevents the default action, so nothing appears in the `<input>` for keys that don't pass the test. (The `true` value returned doesn't affect anything, only returning `false` matters)
 
-Please note that special keys, such as `key:Backspace`, `key:Left`, `key:Right`, `key:Ctrl+V`, do not work in the input. That's a side-effect of the strict filter `checkPhoneKey`.
+Please note that special keys, such as `key:Backspace`, `key:Left`, `key:Right`, do not work in the input. That's a side-effect of the strict filter `checkPhoneKey`.
 
 Let's relax it a little bit by allowing `key:Left`, `key:Right` arrows and `key:Delete`, `key:Backspace`:
 

From 85282ef4ad90e33e6b0a35bdf1fe062cd262693c Mon Sep 17 00:00:00 2001
From: Ilya Kantor <iliakan@gmail.com>
Date: Sat, 19 Jun 2021 18:50:12 +0300
Subject: [PATCH 17/26] minor fixes

---
 2-ui/3-event-details/7-keyboard-events/article.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/2-ui/3-event-details/7-keyboard-events/article.md b/2-ui/3-event-details/7-keyboard-events/article.md
index 6318fde21..78c4bf1f5 100644
--- a/2-ui/3-event-details/7-keyboard-events/article.md
+++ b/2-ui/3-event-details/7-keyboard-events/article.md
@@ -149,9 +149,9 @@ The `onkeydown` handler here uses `checkPhoneKey` to check for the key pressed.
 
 As we know, the `false` value returned from the event handler, assigned using a DOM property or an attribute, such as above, prevents the default action, so nothing appears in the `<input>` for keys that don't pass the test. (The `true` value returned doesn't affect anything, only returning `false` matters)
 
-Please note that special keys, such as `key:Backspace`, `key:Left`, `key:Right`, do not work in the input. That's a side-effect of the strict filter `checkPhoneKey`.
+Please note that special keys, such as `key:Backspace`, `key:Left`, `key:Right`, do not work in the input. That's a side-effect of the strict filter `checkPhoneKey`. These keys make it return `false`.
 
-Let's relax it a little bit by allowing `key:Left`, `key:Right` arrows and `key:Delete`, `key:Backspace`:
+Let's relax the filter a little bit by allowing `key:Left`, `key:Right` arrows and `key:Delete`, `key:Backspace`:
 
 
 ```html autorun height=60 run

From a40ca9a4a3b7624ca95096df9950ea30c0853e95 Mon Sep 17 00:00:00 2001
From: Ilya Kantor <iliakan@gmail.com>
Date: Sat, 19 Jun 2021 18:50:41 +0300
Subject: [PATCH 18/26] minor fixes

---
 2-ui/3-event-details/7-keyboard-events/article.md | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/2-ui/3-event-details/7-keyboard-events/article.md b/2-ui/3-event-details/7-keyboard-events/article.md
index 78c4bf1f5..9639239cd 100644
--- a/2-ui/3-event-details/7-keyboard-events/article.md
+++ b/2-ui/3-event-details/7-keyboard-events/article.md
@@ -151,8 +151,7 @@ As we know, the `false` value returned from the event handler, assigned using a
 
 Please note that special keys, such as `key:Backspace`, `key:Left`, `key:Right`, do not work in the input. That's a side-effect of the strict filter `checkPhoneKey`. These keys make it return `false`.
 
-Let's relax the filter a little bit by allowing `key:Left`, `key:Right` arrows and `key:Delete`, `key:Backspace`:
-
+Let's relax the filter a little bit by allowing arrow keys `key:Left`, `key:Right` and `key:Delete`, `key:Backspace`:
 
 ```html autorun height=60 run
 <script>

From 54347b7116053912ae6d58d93be98121eab2bbdd Mon Sep 17 00:00:00 2001
From: Ilya Kantor <iliakan@gmail.com>
Date: Sat, 19 Jun 2021 18:50:59 +0300
Subject: [PATCH 19/26] minor fixes

---
 2-ui/3-event-details/7-keyboard-events/article.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/2-ui/3-event-details/7-keyboard-events/article.md b/2-ui/3-event-details/7-keyboard-events/article.md
index 9639239cd..f683e1f7e 100644
--- a/2-ui/3-event-details/7-keyboard-events/article.md
+++ b/2-ui/3-event-details/7-keyboard-events/article.md
@@ -157,7 +157,7 @@ Let's relax the filter a little bit by allowing arrow keys `key:Left`, `key:Righ
 <script>
 function checkPhoneKey(key) {
   return (key >= '0' && key <= '9') ||
-    ['+','(',')','-','ArrowLeft','ArrowRight','Delete','Backspace'].includes(key);
+    ['+','(',')','-',*!*'ArrowLeft','ArrowRight','Delete','Backspace'*/!*].includes(key);
 }
 </script>
 <input onkeydown="return checkPhoneKey(event.key)" placeholder="Phone, please" type="tel">

From df6e5a4522e83a071d5c0013648d2839f5b68345 Mon Sep 17 00:00:00 2001
From: Ilya Kantor <iliakan@gmail.com>
Date: Sat, 19 Jun 2021 18:53:06 +0300
Subject: [PATCH 20/26] minor fixes

---
 2-ui/3-event-details/7-keyboard-events/article.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/2-ui/3-event-details/7-keyboard-events/article.md b/2-ui/3-event-details/7-keyboard-events/article.md
index f683e1f7e..cea96a101 100644
--- a/2-ui/3-event-details/7-keyboard-events/article.md
+++ b/2-ui/3-event-details/7-keyboard-events/article.md
@@ -165,7 +165,7 @@ function checkPhoneKey(key) {
 
 Now arrows and deletion works well.
 
-...But we still can enter anything by using a mouse and right-click + Paste. So the filter is not 100% reliable. We can just let it be like that, because most of time it works. Or an alternative approach would be to track the `input` event -- it triggers after any modification. There we can check the new value and highlight/modify it when it's invalid.
+Even though we have the key filter, one still can enter anything using a mouse and right-click + Paste. So the filter is not 100% reliable. We can just let it be like that, because most of time it works. Or an alternative approach would be to track the `input` event -- it triggers after any modification. There we can check the new value and highlight/modify it when it's invalid.
 
 ## Legacy
 

From e769408d640e325233fe46c2d30b83edf9b3334d Mon Sep 17 00:00:00 2001
From: Ilya Kantor <iliakan@gmail.com>
Date: Sat, 19 Jun 2021 18:55:00 +0300
Subject: [PATCH 21/26] minor fixes

---
 2-ui/3-event-details/7-keyboard-events/article.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/2-ui/3-event-details/7-keyboard-events/article.md b/2-ui/3-event-details/7-keyboard-events/article.md
index cea96a101..0af3cee42 100644
--- a/2-ui/3-event-details/7-keyboard-events/article.md
+++ b/2-ui/3-event-details/7-keyboard-events/article.md
@@ -165,7 +165,7 @@ function checkPhoneKey(key) {
 
 Now arrows and deletion works well.
 
-Even though we have the key filter, one still can enter anything using a mouse and right-click + Paste. So the filter is not 100% reliable. We can just let it be like that, because most of time it works. Or an alternative approach would be to track the `input` event -- it triggers after any modification. There we can check the new value and highlight/modify it when it's invalid.
+Even though we have the key filter, one still can enter anything using a mouse and right-click + Paste. So the filter is not 100% reliable. The more reliable approach would be to track the `input` event -- it triggers after any modification. There we can check the new value and highlight/modify it when it's invalid.
 
 ## Legacy
 

From de81cb4809ca3147a6c5cede2fb60c9af1e5dc54 Mon Sep 17 00:00:00 2001
From: Ilya Kantor <iliakan@gmail.com>
Date: Sat, 19 Jun 2021 18:58:37 +0300
Subject: [PATCH 22/26] minor fixes

---
 2-ui/3-event-details/7-keyboard-events/article.md | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/2-ui/3-event-details/7-keyboard-events/article.md b/2-ui/3-event-details/7-keyboard-events/article.md
index 0af3cee42..8a15e657a 100644
--- a/2-ui/3-event-details/7-keyboard-events/article.md
+++ b/2-ui/3-event-details/7-keyboard-events/article.md
@@ -165,7 +165,9 @@ function checkPhoneKey(key) {
 
 Now arrows and deletion works well.
 
-Even though we have the key filter, one still can enter anything using a mouse and right-click + Paste. So the filter is not 100% reliable. The more reliable approach would be to track the `input` event -- it triggers after any modification. There we can check the new value and highlight/modify it when it's invalid.
+Even though we have the key filter, one still can enter anything using a mouse and right-click + Paste. So the filter is not 100% reliable.
+
+The alternative approach would be to track the `oninput` event -- it triggers *after* any modification. There we can check the new `input.value` and highlight/modify the `<input>` when it's invalid. Or we can use both event handlers together.
 
 ## Legacy
 

From 7dacfd411b4d99536b02df5200a4e4f5078adff3 Mon Sep 17 00:00:00 2001
From: Ilya Kantor <iliakan@gmail.com>
Date: Sat, 19 Jun 2021 18:59:04 +0300
Subject: [PATCH 23/26] minor fixes

---
 2-ui/3-event-details/7-keyboard-events/article.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/2-ui/3-event-details/7-keyboard-events/article.md b/2-ui/3-event-details/7-keyboard-events/article.md
index 8a15e657a..bdfcff308 100644
--- a/2-ui/3-event-details/7-keyboard-events/article.md
+++ b/2-ui/3-event-details/7-keyboard-events/article.md
@@ -167,7 +167,7 @@ Now arrows and deletion works well.
 
 Even though we have the key filter, one still can enter anything using a mouse and right-click + Paste. So the filter is not 100% reliable.
 
-The alternative approach would be to track the `oninput` event -- it triggers *after* any modification. There we can check the new `input.value` and highlight/modify the `<input>` when it's invalid. Or we can use both event handlers together.
+The alternative approach would be to track the `oninput` event -- it triggers *after* any modification. There we can check the new `input.value` and modify it/highlight the `<input>` when it's invalid. Or we can use both event handlers together.
 
 ## Legacy
 

From 36613935fea17fe8e0e85dd14c9af0dd3d5b5ac8 Mon Sep 17 00:00:00 2001
From: Ilya Kantor <iliakan@gmail.com>
Date: Sat, 19 Jun 2021 18:59:39 +0300
Subject: [PATCH 24/26] minor fixes

---
 2-ui/3-event-details/7-keyboard-events/article.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/2-ui/3-event-details/7-keyboard-events/article.md b/2-ui/3-event-details/7-keyboard-events/article.md
index bdfcff308..51c1618f6 100644
--- a/2-ui/3-event-details/7-keyboard-events/article.md
+++ b/2-ui/3-event-details/7-keyboard-events/article.md
@@ -165,7 +165,7 @@ function checkPhoneKey(key) {
 
 Now arrows and deletion works well.
 
-Even though we have the key filter, one still can enter anything using a mouse and right-click + Paste. So the filter is not 100% reliable.
+Even though we have the key filter, one still can enter anything using a mouse and right-click + Paste. Mobile devices provide other means to enter values. So the filter is not 100% reliable.
 
 The alternative approach would be to track the `oninput` event -- it triggers *after* any modification. There we can check the new `input.value` and modify it/highlight the `<input>` when it's invalid. Or we can use both event handlers together.
 

From 52eaa63aaa0f7f0bdcd739cc3f7e915f32dfd249 Mon Sep 17 00:00:00 2001
From: joaquinelio <joaquinelio@gmail.com>
Date: Sat, 19 Jun 2021 21:21:24 -0300
Subject: [PATCH 25/26] typo

---
 1-js/04-object-basics/09-object-toprimitive/article.md | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/1-js/04-object-basics/09-object-toprimitive/article.md b/1-js/04-object-basics/09-object-toprimitive/article.md
index b0605d44f..3e52a1d51 100644
--- a/1-js/04-object-basics/09-object-toprimitive/article.md
+++ b/1-js/04-object-basics/09-object-toprimitive/article.md
@@ -9,7 +9,7 @@ In case of such operations, objects are auto-converted to primitives, and then t
 
 That's an important limitation, as the result of `obj1 + obj2` can't be another object!
 
-E.g. we can't make objects representing vectors or matrices (or archievements or whatever), add them and expect a "summed" object as the result. Such architectural feats are automatically "off the board".
+E.g. we can't make objects representing vectors or matrices (or achievements or whatever), add them and expect a "summed" object as the result. Such architectural feats are automatically "off the board".
 
 So, because we can't do much here, there's no maths with objects in real projects. When it happens, it's usually because of a coding mistake.
 
@@ -133,7 +133,7 @@ As we can see from the code, `user` becomes a self-descriptive string or a money
 
 If there's no `Symbol.toPrimitive` then JavaScript tries to find methods `toString` and `valueOf`:
 
-- For the "string" hint: `toString`, and if it doesn't exist, then `valueOf` (so `toString` has the priority for stirng conversions).
+- For the "string" hint: `toString`, and if it doesn't exist, then `valueOf` (so `toString` has the priority for string conversions).
 - For other hints: `valueOf`, and if it doesn't exist, then `toString` (so `valueOf` has the priority for maths).
 
 Methods `toString` and `valueOf` come from ancient times. They are not symbols (symbols did not exist that long ago), but rather "regular" string-named methods. They provide an alternative "old-style" way to implement the conversion.
@@ -274,4 +274,4 @@ The conversion algorithm is:
 
 In practice, it's often enough to implement only `obj.toString()` as a "catch-all" method for string conversions that should return a "human-readable" representation of an object, for logging or debugging purposes.  
 
-As for math operations, JavaScript doesn't provide a way to "override" them using methods, so real life projects rarely use them on objects.
\ No newline at end of file
+As for math operations, JavaScript doesn't provide a way to "override" them using methods, so real life projects rarely use them on objects.

From 9847492838326ea9c161aebeb1ebb6749bd1f5cd Mon Sep 17 00:00:00 2001
From: Elena Valeeva <elena243v@gmail.com>
Date: Sun, 20 Jun 2021 08:12:59 +0300
Subject: [PATCH 26/26] Typo in Ch 15 Functions

---
 1-js/02-first-steps/15-function-basics/article.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/1-js/02-first-steps/15-function-basics/article.md b/1-js/02-first-steps/15-function-basics/article.md
index ac6f1f47c..09ad90dc0 100644
--- a/1-js/02-first-steps/15-function-basics/article.md
+++ b/1-js/02-first-steps/15-function-basics/article.md
@@ -247,7 +247,7 @@ function showMessage(text) {
 showMessage(); // empty message
 ```
 
-...Or we could use the `??` operator:
+...Or we could use the `||` operator:
 
 ```js
 function showMessage(text) {