diff options
Diffstat (limited to 'files/pl/web/javascript/reference/global_objects/string/fromcodepoint/index.html')
| -rw-r--r-- | files/pl/web/javascript/reference/global_objects/string/fromcodepoint/index.html | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/files/pl/web/javascript/reference/global_objects/string/fromcodepoint/index.html b/files/pl/web/javascript/reference/global_objects/string/fromcodepoint/index.html new file mode 100644 index 0000000000..d929675696 --- /dev/null +++ b/files/pl/web/javascript/reference/global_objects/string/fromcodepoint/index.html @@ -0,0 +1,150 @@ +--- +title: String.fromCodePoint() +slug: Web/JavaScript/Reference/Global_Objects/String/fromCodePoint +translation_of: Web/JavaScript/Reference/Global_Objects/String/fromCodePoint +original_slug: Web/JavaScript/Referencje/Obiekty/String/fromCodePoint +--- +<div>{{JSRef}}</div> + +<p>The static <strong><code>String.fromCodePoint()</code></strong> method returns a string created by using the specified sequence of code points.</p> + +<div>{{EmbedInteractiveExample("pages/js/string-fromcodepoint.html","shorter")}}</div> + + + +<h2 id="Syntax">Syntax</h2> + +<pre class="syntaxbox notranslate">String<code>.fromCodePoint(<var>num1</var>[, ...[, <var>numN</var>]])</code></pre> + +<h3 id="Parameters">Parameters</h3> + +<dl> + <dt><code><var>num1</var>, ..., <var>numN</var></code></dt> + <dd>A sequence of code points.</dd> +</dl> + +<h3 id="Return_value">Return value</h3> + +<p>A string created by using the specified sequence of code points.</p> + +<h3 id="Exceptions">Exceptions</h3> + +<ul> + <li>A {{jsxref("Errors/Not_a_codepoint", "RangeError")}} is thrown if an invalid Unicode code point is given (e.g. <code>"RangeError: NaN is not a valid code point"</code>).</li> +</ul> + +<h2 id="Description">Description</h2> + +<p>This method returns a string (and <em>not</em> a {{jsxref("String")}} object).</p> + +<p>Because <code>fromCodePoint()</code> is a static method of {{jsxref("String")}}, you must call it as <code>String.fromCodePoint()</code>, rather than as a method of a {{jsxref("String")}} object you created.</p> + +<h2 id="Polyfill">Polyfill</h2> + +<p>The <code>String.fromCodePoint()</code> method has been added to ECMAScript 2015 and may not be supported in all web browsers or environments yet.</p> + +<p>Use the code below for a polyfill:</p> + +<pre class="brush: js notranslate">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="Examples">Examples</h2> + +<h3 id="Using_fromCodePoint">Using <code>fromCodePoint()</code></h3> + +<p>Valid input:</p> + +<pre class="brush: js notranslate">String.fromCodePoint(42); // "*" +String.fromCodePoint(65, 90); // "AZ" +String.fromCodePoint(0x404); // "\u0404" == "Є" +String.fromCodePoint(0x2F804); // "\uD87E\uDC04" +String.fromCodePoint(194564); // "\uD87E\uDC04" +String.fromCodePoint(0x1D306, 0x61, 0x1D307); // "\uD834\uDF06a\uD834\uDF07" +</pre> + +<p>Invalid input:</p> + +<pre class="brush: js notranslate">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> + +<h3 id="Compared_to_fromCharCode">Compared to <code>fromCharCode()</code></h3> + +<p>{{jsxref("String.fromCharCode()")}} cannot return supplementary characters (i.e. code points <code>0x010000</code> – <code>0x10FFFF</code>) by specifying their code point. Instead, it requires the UTF-16 surrogate pair in order to return a supplementary character:</p> + +<pre class="brush: js notranslate">String.fromCharCode(0xD83C, 0xDF03); // Code Point U+1F303 "Night with +String.fromCharCode(55356, 57091); // Stars" == "\uD83C\uDF03" +</pre> + +<p><code>String.fromCodePoint()</code>, on the other hand, can return 4-byte supplementary characters, as well as the more common 2-byte BMP characters, by specifying their code point (which is equivalent to the UTF-32 code unit):</p> + +<pre class="brush: js notranslate">String.fromCodePoint(0x1F303); // or 127747 in decimal +</pre> + +<h2 id="Specifications">Specifications</h2> + +<table class="standard-table"> + <thead> + <tr> + <th scope="col">Specification</th> + </tr> + </thead> + <tbody> + <tr> + <td>{{SpecName('ESDraft', '#sec-string.fromcodepoint', 'String.fromCodePoint')}}</td> + </tr> + </tbody> +</table> + +<h2 id="Browser_compatibility">Browser compatibility</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">See also</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> |