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diff --git a/files/ja/web/javascript/reference/global_objects/string/fromcodepoint/index.html b/files/ja/web/javascript/reference/global_objects/string/fromcodepoint/index.html new file mode 100644 index 0000000000..c8bcbf6ae3 --- /dev/null +++ b/files/ja/web/javascript/reference/global_objects/string/fromcodepoint/index.html @@ -0,0 +1,149 @@ +--- +title: String.fromCodePoint() +slug: Web/JavaScript/Reference/Global_Objects/String/fromCodePoint +tags: + - ECMAScript 2015 + - JavaScript + - Method + - Reference + - String +translation_of: Web/JavaScript/Reference/Global_Objects/String/fromCodePoint +--- +<div>{{JSRef}}</div> + +<p><strong><code>String.fromCodePoint()</code></strong> 静的メソッドは指定されたコードポイントのシーケンスを使って生成された文字列を返します。</p> + +<div>{{EmbedInteractiveExample("pages/js/string-fromcodepoint.html")}}</div> + + + +<h2 id="Syntax" name="Syntax">構文</h2> + +<pre class="syntaxbox"><code>String.fromCodePoint(<var>num1</var>[, ...[, <var>numN</var>]])</code></pre> + +<h3 id="Parameters" name="Parameters">引数</h3> + +<dl> + <dt><code>num1, ..., num<em>N</em></code></dt> + <dd>コードポイントのシーケンスです。</dd> +</dl> + +<h3 id="Return_value" name="Return_value">戻り値</h3> + +<p>指定されたコードポイントのシーケンスを使って生成された文字列です。</p> + +<h3 id="Exceptions" name="Exceptions">例外</h3> + +<ul> + <li>無効な Unicode コードポイントを与えられた場合、{{jsxref("Errors/Not_a_codepoint", "RangeError")}} （例: "RangeError: NaN is not a valid code point" ）がスローされます。</li> +</ul> + +<h2 id="Description" name="Description">説明</h2> + +<p>このメソッドは {{jsxref("String")}} オブジェクトではなく文字列を返します。</p> + +<p><code>fromCodePoint()</code> メソッドは {{jsxref("String")}} の静的なメソッドなので、自ら生成した {{jsxref("String")}} オブジェクトのメソッドとしてではなく、常に <code>String.fromCodePoint()</code> として使用してください。</p> + +<h2 id="Examples" name="Examples">例</h2> + +<h3 id="Using_fromCharCode" name="Using_fromCharCode"><code>fromCodePoint()</code> を使う</h3> + +<pre class="brush: js">String.fromCodePoint(42); // "*" +String.fromCodePoint(65, 90); // "AZ" +String.fromCodePoint(0x404); // "\u0404" +String.fromCodePoint(0x2F804); // "\uD87E\uDC04" +String.fromCodePoint(194564); // "\uD87E\uDC04" +String.fromCodePoint(0x1D306, 0x61, 0x1D307) // "\uD834\uDF06a\uD834\uDF07" + +String.fromCodePoint('_'); // RangeError +String.fromCodePoint(Infinity); // RangeError +String.fromCodePoint(-1); // RangeError +String.fromCodePoint(3.14); // RangeError +String.fromCodePoint(3e-2); // RangeError +String.fromCodePoint(NaN); // RangeError +</pre> + +<pre class="brush: js">// String.fromCharCode() alone cannot get the character at such a high code point +// The following, on the other hand, can return a 4-byte character as well as the +// usual 2-byte ones (i.e., it can return a single character which actually has +// a string length of 2 instead of 1!) +console.log(String.fromCodePoint(0x2F804)); // or 194564 in decimal +</pre> + +<h2 id="Polyfill" name="Polyfill">ポリフィル</h2> + +<p><code>String.fromCodePoint</code> メソッドは ECMAScript 2015 で追加されました。まだすべての Web ブラウザーや環境でサポートされていないかもしれません。互換性のために次のコードを使用してください。</p> + +<pre class="brush: js">if (!String.fromCodePoint) (function(stringFromCharCode) { + var fromCodePoint = function(_) { + var codeUnits = [], codeLen = 0, result = ""; + for (var index=0, len = arguments.length; index !== len; ++index) { + var codePoint = +arguments[index]; + // correctly handles all cases including `NaN`, `-Infinity`, `+Infinity` + // The surrounding `!(...)` is required to correctly handle `NaN` cases + // The (codePoint>>>0) === codePoint clause handles decimals and negatives + if (!(codePoint < 0x10FFFF && (codePoint>>>0) === codePoint)) + throw RangeError("Invalid code point: " + codePoint); + if (codePoint <= 0xFFFF) { // BMP code point + codeLen = codeUnits.push(codePoint); + } else { // Astral code point; split in surrogate halves + // https://mathiasbynens.be/notes/javascript-encoding#surrogate-formulae + codePoint -= 0x10000; + codeLen = codeUnits.push( + (codePoint >> 10) + 0xD800, // highSurrogate + (codePoint % 0x400) + 0xDC00 // lowSurrogate + ); + } + if (codeLen >= 0x3fff) { + result += stringFromCharCode.apply(null, codeUnits); + codeUnits.length = 0; + } + } + return result + stringFromCharCode.apply(null, codeUnits); + }; + try { // IE 8 only supports `Object.defineProperty` on DOM elements + Object.defineProperty(String, "fromCodePoint", { + "value": fromCodePoint, "configurable": true, "writable": true + }); + } catch(e) { + String.fromCodePoint = fromCodePoint; + } +}(String.fromCharCode)); +</pre> + +<h2 id="Specifications" name="Specifications">仕様</h2> + +<table class="standard-table"> + <tbody> + <tr> + <th scope="col">仕様</th> + <th scope="col">状況</th> + <th scope="col">コメント</th> + </tr> + <tr> + <td>{{SpecName('ES2015', '#sec-string.fromcodepoint', 'String.fromCodePoint')}}</td> + <td>{{Spec2('ES2015')}}</td> + <td>初期定義</td> + </tr> + <tr> + <td>{{SpecName('ESDraft', '#sec-string.fromcodepoint', 'String.fromCodePoint')}}</td> + <td>{{Spec2('ESDraft')}}</td> + <td></td> + </tr> + </tbody> +</table> + +<h2 id="Browser_compatibility" name="Browser_compatibility">ブラウザー実装状況</h2> + +<p class="hidden">The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out <a href="https://github.com/mdn/browser-compat-data">https://github.com/mdn/browser-compat-data</a> and send us a pull request.</p> + +<p>{{Compat("javascript.builtins.String.fromCodePoint")}}</p> + +<h2 id="See_also" name="See_also">関連情報</h2> + +<ul> + <li>{{jsxref("String.fromCharCode()")}}</li> + <li>{{jsxref("String.prototype.charAt()")}}</li> + <li>{{jsxref("String.prototype.codePointAt()")}}</li> + <li>{{jsxref("String.prototype.charCodeAt()")}}</li> +</ul> |