From 33058f2b292b3a581333bdfb21b8f671898c5060 Mon Sep 17 00:00:00 2001
From: Peter Bengtsson <mail@peterbe.com>
Date: Tue, 8 Dec 2020 14:40:17 -0500
Subject: initial commit

---
 .../operators/addition_assignment/index.html       | 78 ++++++++++++++++++++++
 1 file changed, 78 insertions(+)
 create mode 100644 files/ja/web/javascript/reference/operators/addition_assignment/index.html

(limited to 'files/ja/web/javascript/reference/operators/addition_assignment/index.html')

diff --git a/files/ja/web/javascript/reference/operators/addition_assignment/index.html b/files/ja/web/javascript/reference/operators/addition_assignment/index.html
new file mode 100644
index 0000000000..d2e2a59492
--- /dev/null
+++ b/files/ja/web/javascript/reference/operators/addition_assignment/index.html
@@ -0,0 +1,78 @@
+---
+title: 加算代入 (+=)
+slug: Web/JavaScript/Reference/Operators/Addition_assignment
+tags:
+  - Assignment operator
+  - JavaScript
+  - Language feature
+  - Operator
+  - Reference
+translation_of: Web/JavaScript/Reference/Operators/Addition_assignment
+---
+<div>{{jsSidebar("Operators")}}</div>
+
+<p>加算代入演算子 (<code>+=</code>) は、右辺のオペランドの値を変数に加算し、結果を変数に代入します。 2つのオペランドの型は、加算代入演算子の動作を決定します。加算もしくは連結が可能です。</p>
+
+<div>{{EmbedInteractiveExample("pages/js/expressions-addition-assignment.html")}}</div>
+
+<div></div>
+
+
+
+<h2 id="構文">構文</h2>
+
+<pre class="syntaxbox notranslate"><strong>Operator:</strong> x += y
+<strong>Meaning:</strong>  x  = x + y</pre>
+
+<h2 id="例">例</h2>
+
+<h3 id="加算代入の使用">加算代入の使用</h3>
+
+<pre class="brush: js notranslate">// 以下の変数を想定
+//  foo = 'foo'
+//  bar = 5
+//  baz = true
+
+// 数値 + 数値 -&gt; 加算
+bar += 2 // 7
+
+// ブール値 + 数値 -&gt; 加算
+baz += 1 // 2
+
+// ブール値 + ブール値 -&gt; 加算
+baz += false // 1
+
+// 数値 + 文字列 -&gt; 連結
+bar += 'foo' // "5foo"
+
+// 文字列 + ブール値 -&gt; 連結
+foo += false // "foofalse"
+
+// 文字列 + 文字列 -&gt; 連結
+foo += 'bar' // "foobar"</pre>
+
+<h2 id="仕様">仕様</h2>
+
+<table class="standard-table">
+ <tbody>
+  <tr>
+   <th scope="col">仕様</th>
+  </tr>
+  <tr>
+   <td>{{SpecName('ESDraft', '#sec-assignment-operators', 'Assignment operators')}}</td>
+  </tr>
+ </tbody>
+</table>
+
+<h2 id="ブラウザーの互換性">ブラウザーの互換性</h2>
+
+
+
+<p>{{Compat("javascript.operators.addition_assignment")}}</p>
+
+<h2 id="関連項目">関連項目</h2>
+
+<ul>
+ <li><a href="/docs/Web/JavaScript/Guide/Expressions_and_Operators#Assignment">代入演算子</a></li>
+ <li><a href="/docs/Web/JavaScript/Reference/Operators/Addition">加算演算子</a></li>
+</ul>
-- 
cgit v1.2.3-54-g00ecf