From 1bd12b70b8feee3216f50ec38e0c009a6945f91e Mon Sep 17 00:00:00 2001
From: Vlad Esin <44160260+svetley1@users.noreply.github.com>
Date: Fri, 13 Sep 2019 16:38:14 +0500
Subject: [PATCH 1/2] Short-circuit evaluation and return for && | |
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1) && возвращает первый операнд который привелся к false. Если такового не оказалось, то возвращается последний операнд (истинный).
2 && 0 && 'string' => 0
'' && 4 => ''
0 && 6 => 0
4 && 3 => 3
2) || возвращает первый операнд который привелся к true. Если такового не оказалось, то возвращается последний операнд (ложный).
'' || 4 => 4
0 || 6 => 6
4 || 3 => 4
'' || 0 || null => null

Так же следует отметить, что используются 'short-circuit evaluation', то есть функция f() в примере ниже не исполнится.
'' || true || f() => true
---
 Javascript/2-logical-operators.js | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/Javascript/2-logical-operators.js b/Javascript/2-logical-operators.js
index c0d8588..b46d9fb 100644
--- a/Javascript/2-logical-operators.js
+++ b/Javascript/2-logical-operators.js
@@ -16,6 +16,12 @@ console.log('Mix of Tea AND Juice is ' + goodDrinks);
 console.log('Mix of Vodka AND Beer is ' + badDrinks);
 console.log('Mix of Vodka AND Juice is ' + badMix);
 
+const logicalAndFirstFalse = 'string' && 0 && 10; // 0
+console.log('\'string\' && 0 && 10 => ' + logicalAndFirstFalse)
+
+const logicalAndLastTrue = 'string' && 5 && 10; // 10
+console.log('\'string\' && 5 && 10 => ' + logicalAndLastTrue)
+
 const engine1 = true;
 const engine2 = false;
 
@@ -27,6 +33,12 @@ console.log('The first engine works? - ' + engine1);
 console.log('The second engine works? - ' + engine2);
 console.log('Is the plane still flying? - ' + fly);
 
+const logicalOrFirstTrue = 'string' || 0 || 10; // 'string'
+console.log('\'string\' || 0 || 10 => ' + logicalOrFirstTrue)
+
+const logicalOrLastFalse = '' || null || 0; // 0
+console.log('\'\' || null || 0 => ' + logicalOrLastFalse)
+
 const happy = true;
 
 const mood = !happy; // false

From e708a12f3dfcc8a8a2a1600d780a25bb03ecb5b0 Mon Sep 17 00:00:00 2001
From: Vlad Esin <44160260+svetley1@users.noreply.github.com>
Date: Fri, 13 Sep 2019 22:30:03 +0500
Subject: [PATCH 2/2] Code style

---
 Javascript/2-logical-operators.js | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/Javascript/2-logical-operators.js b/Javascript/2-logical-operators.js
index b46d9fb..0075455 100644
--- a/Javascript/2-logical-operators.js
+++ b/Javascript/2-logical-operators.js
@@ -17,10 +17,10 @@ console.log('Mix of Vodka AND Beer is ' + badDrinks);
 console.log('Mix of Vodka AND Juice is ' + badMix);
 
 const logicalAndFirstFalse = 'string' && 0 && 10; // 0
-console.log('\'string\' && 0 && 10 => ' + logicalAndFirstFalse)
+console.log('\'string\' && 0 && 10 => ' + logicalAndFirstFalse);
 
 const logicalAndLastTrue = 'string' && 5 && 10; // 10
-console.log('\'string\' && 5 && 10 => ' + logicalAndLastTrue)
+console.log('\'string\' && 5 && 10 => ' + logicalAndLastTrue);
 
 const engine1 = true;
 const engine2 = false;
@@ -34,10 +34,10 @@ console.log('The second engine works? - ' + engine2);
 console.log('Is the plane still flying? - ' + fly);
 
 const logicalOrFirstTrue = 'string' || 0 || 10; // 'string'
-console.log('\'string\' || 0 || 10 => ' + logicalOrFirstTrue)
+console.log('\'string\' || 0 || 10 => ' + logicalOrFirstTrue);
 
 const logicalOrLastFalse = '' || null || 0; // 0
-console.log('\'\' || null || 0 => ' + logicalOrLastFalse)
+console.log('\'\' || null || 0 => ' + logicalOrLastFalse);
 
 const happy = true;