--- title: String.prototype.includes() slug: Web/JavaScript/Reference/Global_Objects/String/includes tags: - JavaScript - Method - Prototype - Reference - String translation_of: Web/JavaScript/Reference/Global_Objects/String/includes --- <div>{{JSRef}}</div> <p><strong><code>includes()</code></strong> 메서드는 하나의 문자열이 다른 문자열에 포함되어 있는지를 판별하고, 결과를 <code>true</code> 또는 <code>false</code> 로 반환합니다.</p> <p>{{EmbedInteractiveExample("pages/js/string-includes.html")}}</p> <h2 id="구문">구문</h2> <pre class="syntaxbox"><code><var>str</var>.includes(<var>searchString</var>[, <var>position</var>])</code></pre> <h3 id="매개변수">매개변수</h3> <dl> <dt><code>searchString</code></dt> <dd>이 문자열에서 찾을 다른 문자열.</dd> <dt><code>position</code> {{optional_inline}}</dt> <dd><code>searchString</code>을 찾기 시작할 위치. 기본값 0.</dd> </dl> <h3 id="반환값">반환값</h3> <p>문자열을 찾아내면 <code>true</code>. 실패하면 <code>false</code>.</p> <h2 id="설명">설명</h2> <p><code>includes()</code> 메서드를 사용해 문자열 내에 찾고자 하는 다른 문자열이 있는지 확인할 수 있습니다.</p> <h3 id="대소문자_구분">대소문자 구분</h3> <p><code>includes()</code> 메서드는 대소문자를 구별합니다. 예를 들어 아래 코드는 <code>false</code>를 반환합니다.</p> <pre class="brush: js">'Blue Whale'.includes('blue'); // returns false </pre> <h2 id="예제">예제</h2> <h3 id="includes()_사용하기"><code>includes()</code> 사용하기</h3> <pre class="brush: js">var str = 'To be, or not to be, that is the question.'; console.log(str.includes('To be')); // true console.log(str.includes('question')); // true console.log(str.includes('nonexistent')); // false console.log(str.includes('To be', 1)); // false console.log(str.includes('TO BE')); // false </pre> <h2 id="폴리필">폴리필</h2> <p>이 메서드는 ECMAScript 6 규격에 포함되었습니다만 아직까지는 모든 JavaScrpt가 이 기능을 지원하고 있지는 않습니다. 하지만 여러분은 이 메서드를 다음과 같이 쉽게 <a href="https://en.wikipedia.org/wiki/Polyfill">polyfill</a> 할 수 있습니다.</p> <pre class="brush: js">if (!String.prototype.includes) { String.prototype.includes = function(search, start) { 'use strict'; if (typeof start !== 'number') { start = 0; } if (start + search.length > this.length) { return false; } else { return this.indexOf(search, start) !== -1; } }; } </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('ES6', '#sec-string.prototype.includes', 'String.prototype.includes')}}</td> <td>{{Spec2('ES6')}}</td> <td>Initial definition.</td> </tr> <tr> <td>{{SpecName('ESDraft', '#sec-string.prototype.includes', 'String.prototype.includes')}}</td> <td>{{Spec2('ESDraft')}}</td> <td> </td> </tr> </tbody> </table> <h2 id="브라우저_호환성">브라우저 호환성</h2> <div>{{Compat("javascript.builtins.String.includes")}}</div> <h2 id="String.prototype.contains">String.prototype.contains</h2> <p>Firefox 18 - 39에서, <code>include()</code> 메서드의 이름은 <code>contains()</code>이었습니다. contains() 함수는 아래와 같은 이유로 {{bug(1102219)}}에서 <code>includes()</code>로 변경되었습니다:</p> <p>It's been <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=789036">reported</a> that some websites using MooTools 1.2 broke on Firefox 17. This version of MooTools checks whether <code>String.prototype.contains()</code> exists and, if it doesn't, MooTools adds its own function. With the introduction of this function in Firefox 17, the behavior of that check changed in a way that causes code based on MooTools' <code>String.prototype.contains()</code> implementation to break. As a result, the implementation was <a href="https://hg.mozilla.org/releases/mozilla-aurora/rev/086db97198a8">disabled</a> in Firefox 17 and <code>String.prototype.contains()</code> was available one version later, in Firefox 18, when <a href="https://bugzilla.mozilla.org/show_bug.cgi?id=789036#c32">outreach to MooTools </a>was leading to the <a href="http://mootools.net/blog/2013/02/19/mootools-1-2-6-released">release of MooTools version 1.2.6</a>.</p> <p>MooTools 1.3 forces its own version of <code>String.prototype.contains()</code>, so websites relying on it should not break. However, you should note that <a href="http://mootools.net/core/docs/1.3.2/Types/String#String-method:-contains">MooTools 1.3 signature</a> and ECMAScript 6 signatures for this method differ (on the second argument). Later, <a href="https://github.com/mootools/mootools-core/blob/master/Docs/Types/String.md#note">MooTools 1.5+ changed the signature to match the ES6 standard.</a></p> <p>Firefox 48에서, <code>String.prototype.contains()</code>은 제거되었습니다. 오직 <code>String.prototype.includes()</code>만 사용할 수 있습니다.</p> <h2 id="관련문서">관련문서</h2> <ul> <li>{{jsxref("Array.prototype.includes()")}} {{experimental_inline}}</li> <li>{{jsxref("TypedArray.prototype.includes()")}} {{experimental_inline}}</li> <li>{{jsxref("String.prototype.indexOf()")}}</li> <li>{{jsxref("String.prototype.lastIndexOf()")}}</li> <li>{{jsxref("String.prototype.startsWith()")}}</li> <li>{{jsxref("String.prototype.endsWith()")}}</li> </ul>