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+---
+title: Array.prototype.includes()
+slug: Web/JavaScript/Reference/Global_Objects/Array/includes
+tags:
+  - Array
+  - JavaScript
+  - Method
+  - Prototype
+  - Reference
+  - polyfill
+translation_of: Web/JavaScript/Reference/Global_Objects/Array/includes
+---
+<div>{{JSRef}}</div>
+
+<p><strong><code>includes()</code></strong> 메서드는 배열이 특정 요소를 포함하고 있는지 판별합니다.</p>
+
+<div>{{EmbedInteractiveExample("pages/js/array-includes.html")}}</div>
+
+
+
+<h2 id="구문">구문</h2>
+
+<pre class="syntaxbox"><var>arr</var>.includes(<em>valueToFind</em>[, <em>fromIndex</em>])
+</pre>
+
+<h3 id="매개변수">매개변수</h3>
+
+<dl>
+ <dt><font face="consolas, Liberation Mono, courier, monospace"><span style="background-color: rgba(220, 220, 220, 0.5);">valueToFind</span></font></dt>
+ <dd>탐색할 요소.
+ <div class="blockIndicator note">
+ <p><strong>참고</strong>: 문자나 문자열을 비교할 때, <code>includes()</code>는 <strong>대소문자를 구분</strong>합니다.</p>
+ </div>
+ </dd>
+ <dt><code>fromIndex</code> {{optional_inline}}</dt>
+ <dd>이 배열에서 searchElement 검색을 시작할 위치입니다. 음의 값은 array.length + fromIndex의 인덱스를 asc로 검색합니다. 기본값은 0입니다.</dd>
+</dl>
+
+<h3 id="반환_값">반환 값</h3>
+
+<p>{{jsxref("Boolean")}}.</p>
+
+<h2 id="예제">예제</h2>
+
+<pre class="brush: js">[1, 2, 3].includes(2);     // true
+[1, 2, 3].includes(4);     // false
+[1, 2, 3].includes(3, 3);  // false
+[1, 2, 3].includes(3, -1); // true
+[1, 2, NaN].includes(NaN); // true
+</pre>
+
+<h3 id="fromIndex_가_배열의_길이보다_같거나_큰_경우"><code>fromIndex</code> 가 배열의 길이보다 같거나 큰 경우</h3>
+
+<p><code>fromIndex</code> 가 배열의 길이보다 같거나 크다면, <code>false</code> 를 반환합니다. 배열은 검색되지 않을 것입니다.</p>
+
+<pre class="brush: js">var arr = ['a', 'b', 'c'];
+
+arr.includes('c', 3);   // false
+arr.includes('c', 100); // false</pre>
+
+<h3 id="0보다_작은_인덱스의_계산">0보다 작은 인덱스의 계산</h3>
+
+<p><code>fromIndex</code> 가 음수라면, 이 계산된 인덱스는 <font face="consolas, Liberation Mono, courier, monospace"><span style="background-color: rgba(220, 220, 220, 0.5);">valueToFind</span></font> 를 찾기 시작할 배열의 위치로 사용되기 위해 연산됩니다. 만약 계산된 인덱스가 <code>-1 * array.length</code> 보다 작거나 같다면, 전체 배열이 검색될 것입니다.</p>
+
+<pre class="brush: js">// array length is 3
+// fromIndex is -100
+// computed index is 3 + (-100) = -97
+
+var arr = ['a', 'b', 'c'];
+
+arr.includes('a', -100); // true
+arr.includes('b', -100); // true
+arr.includes('c', -100); // true
+arr.includes('a', -2); // false</pre>
+
+<h3 id="제네릭_메소드로_사용되는_includes">제네릭 메소드로 사용되는 <code>includes()</code></h3>
+
+<p><code>includes()</code> 메서드는 의도적으로 제네릭입니다. 배열 객체가 되기 위한 <code>this</code> 값을 요구하지 않아, 다른 종류의 객체에 적용될 수 있습니다 (e.g. 유사 배열 객체). 아래 예시는  이 함수의 <a href="/en-US/docs/Web/JavaScript/Reference/Functions/arguments">arguments</a> 객체로 호출되는 <code>includes()</code> 메소드를 보여줍니다.</p>
+
+<pre class="brush: js">(function() {
+  console.log([].includes.call(arguments, 'a')); // true
+  console.log([].includes.call(arguments, 'd')); // false
+})('a','b','c');</pre>
+
+<h2 id="폴리필">폴리필</h2>
+
+<pre class="brush: js"><code>// https://tc39.github.io/ecma262/#sec-array.prototype.includes
+if (!Array.prototype.includes) {
+  Object.defineProperty(Array.prototype, 'includes', {
+    value: function(searchElement, fromIndex) {
+
+      if (this == null) {
+        throw new TypeError('"this" is null or not defined');
+      }
+
+      // 1. Let O be ? ToObject(this value).
+      var o = Object(this);
+
+      // 2. Let len be ? ToLength(? Get(O, "length")).
+      var len = o.length &gt;&gt;&gt; 0;
+
+      // 3. If len is 0, return false.
+      if (len === 0) {
+        return false;
+      }
+
+      // 4. Let n be ? ToInteger(fromIndex).
+      //    (If fromIndex is undefined, this step produces the value 0.)
+      var n = fromIndex | 0;
+
+      // 5. If n ≥ 0, then
+      //  a. Let k be n.
+      // 6. Else n &lt; 0,
+      //  a. Let k be len + n.
+      //  b. If k &lt; 0, let k be 0.
+      var k = Math.max(n &gt;= 0 ? n : len - Math.abs(n), 0);
+
+      function sameValueZero(x, y) {
+        return x === y || (typeof x === 'number' &amp;&amp; typeof y === 'number' &amp;&amp; isNaN(x) &amp;&amp; isNaN(y));
+      }
+
+      // 7. Repeat, while k &lt; len
+      while (k &lt; len) {
+        // a. Let elementK be the result of ? Get(O, ! ToString(k)).
+        // b. If SameValueZero(searchElement, elementK) is true, return true.
+        if (sameValueZero(o[k], searchElement)) {
+          return true;
+        }
+        // c. Increase k by 1.
+        k++;
+      }
+
+      // 8. Return false
+      return false;
+    }
+  });
+}</code></pre>
+
+<h2 id="명세">명세</h2>
+
+<table class="standard-table">
+ <tbody>
+  <tr>
+   <th scope="col">Specification</th>
+   <th scope="col">Status</th>
+   <th scope="col">Comment</th>
+  </tr>
+  <tr>
+   <td>{{SpecName('ES7', '#sec-array.prototype.includes', 'Array.prototype.includes')}}</td>
+   <td>{{Spec2('ES7')}}</td>
+   <td>Initial definition.</td>
+  </tr>
+  <tr>
+   <td>{{SpecName('ESDraft', '#sec-array.prototype.includes', 'Array.prototype.includes')}}</td>
+   <td>{{Spec2('ESDraft')}}</td>
+   <td></td>
+  </tr>
+ </tbody>
+</table>
+
+<h2 id="브라우저_호환성">브라우저 호환성</h2>
+
+<div>{{Compat("javascript.builtins.Array.includes")}}</div>
+
+<h2 id="같이_보기">같이 보기</h2>
+
+<ul>
+ <li>{{jsxref("TypedArray.prototype.includes()")}}</li>
+ <li>{{jsxref("String.prototype.includes()")}}</li>
+ <li>{{jsxref("Array.prototype.indexOf()")}}</li>
+ <li>{{jsxref("Array.prototype.find()")}}</li>
+ <li>{{jsxref("Array.prototype.findIndex()")}}</li>
+</ul>