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author | Peter Bengtsson <mail@peterbe.com> | 2020-12-08 14:42:52 -0500 |
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committer | Peter Bengtsson <mail@peterbe.com> | 2020-12-08 14:42:52 -0500 |
commit | 074785cea106179cb3305637055ab0a009ca74f2 (patch) | |
tree | e6ae371cccd642aa2b67f39752a2cdf1fd4eb040 /files/pt-br/web/javascript/reference/global_objects/arraybuffer | |
parent | da78a9e329e272dedb2400b79a3bdeebff387d47 (diff) | |
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diff --git a/files/pt-br/web/javascript/reference/global_objects/arraybuffer/index.html b/files/pt-br/web/javascript/reference/global_objects/arraybuffer/index.html new file mode 100644 index 0000000000..443a570305 --- /dev/null +++ b/files/pt-br/web/javascript/reference/global_objects/arraybuffer/index.html @@ -0,0 +1,148 @@ +--- +title: ArrayBuffer +slug: Web/JavaScript/Reference/Global_Objects/ArrayBuffer +tags: + - ArrayBuffer + - Constructor + - JavaScript + - TypedArrays +translation_of: Web/JavaScript/Reference/Global_Objects/ArrayBuffer +--- +<p>{{JSRef}}</p> + +<p>O objeto <strong><code>ArrayBuffer</code></strong> é um tipo de dado usado para representar um genérico, <span class="short_text" id="result_box" lang="pt"><span class="hps">buffer de</span> <span class="hps">dados binários</span> <span class="hps">de tamanho</span> <span class="hps">fixo</span></span>. Você não pode manipular diretamente os conteúdos de um <code>ArrayBuffer</code>; em vez disso, você cria um objeto <a href="/en/JavaScript_typed_arrays/ArrayBufferView" title="en/JavaScript typed arrays/ArrayBufferView"><code>ArrayBufferView</code></a> que representa o buffer em um formato específico, e usa para ler e escrever os conteúdos do buffer.</p> + +<p>{{EmbedInteractiveExample("pages/js/arraybuffer-constructor.html")}}</p> + +<div class="hidden"> +<p>The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone <a href="https://github.com/mdn/interactive-examples">https://github.com/mdn/interactive-examples</a> and send us a pull request.</p> +</div> + +<h2 id="Syntax">Syntax</h2> + +<pre>new ArrayBuffer(length) +</pre> + +<h3 id="Parameters">Parameters</h3> + +<dl> + <dt><code>length</code></dt> + <dd>The size, in bytes, of the array buffer to create.</dd> +</dl> + +<h3 id="Return_value">Return value</h3> + +<p>A new <code>ArrayBuffer</code> object of the specified size. Its contents are initialized to 0.</p> + +<h3 id="Exceptions">Exceptions</h3> + +<p>A {{jsxref("RangeError")}} is thrown if the <code>length</code> is larger than {{jsxref("Number.MAX_SAFE_INTEGER")}} (>= 2 ** 53) or negative.</p> + +<h2 id="Description">Description</h2> + +<p>The <code>ArrayBuffer</code> constructor creates a new <code>ArrayBuffer</code> of the given length in bytes.</p> + +<h3 id="Getting_an_array_buffer_from_existing_data">Getting an array buffer from existing data</h3> + +<ul> + <li><a href="https://developer.mozilla.org/en-US/docs/Web/API/WindowBase64/Base64_encoding_and_decoding#Appendix.3A_Decode_a_Base64_string_to_Uint8Array_or_ArrayBuffer">From a Base64 string</a></li> + <li><a href="https://developer.mozilla.org/en-US/docs/Web/API/FileReader#readAsArrayBuffer()">From a local file</a></li> +</ul> + +<h2 id="Properties">Properties</h2> + +<dl> + <dt><code>ArrayBuffer.length</code></dt> + <dd>The <code>ArrayBuffer</code> constructor's length property whose value is 1.</dd> + <dt>{{jsxref("ArrayBuffer.@@species", "get ArrayBuffer[@@species]")}}</dt> + <dd>The constructor function that is used to create derived objects.</dd> + <dt>{{jsxref("ArrayBuffer.prototype")}}</dt> + <dd>Allows the addition of properties to all <code>ArrayBuffer</code> objects.</dd> +</dl> + +<h2 id="Methods">Methods</h2> + +<dl> + <dt>{{jsxref("ArrayBuffer.isView", "ArrayBuffer.isView(arg)")}}</dt> + <dd>Returns <code>true</code> if <code>arg</code> is one of the ArrayBuffer views, such as <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray">typed array objects</a> or a {{jsxref("DataView")}}. Returns <code>false</code> otherwise.</dd> + <dt>{{jsxref("ArrayBuffer.transfer", "ArrayBuffer.transfer(oldBuffer [, newByteLength])")}} {{experimental_inline}}</dt> + <dd> + <p>Returns a new <code>ArrayBuffer</code> whose contents are taken from the <code>oldBuffer</code>'s data and then is either truncated or zero-extended by <code>newByteLength</code>.</p> + </dd> +</dl> + +<h2 id="Instances">Instances</h2> + +<p>All <code>ArrayBuffer</code> instances inherit from {{jsxref("ArrayBuffer.prototype")}}.</p> + +<h3 id="Properties_2">Properties</h3> + +<p>{{page('en-US/Web/JavaScript/Reference/Global_Objects/ArrayBuffer/prototype','Properties')}}</p> + +<h3 id="Methods_2">Methods</h3> + +<p>{{page('en-US/Web/JavaScript/Reference/Global_Objects/ArrayBuffer/prototype','Methods')}}</p> + +<dl> + <dt>{{jsxref("ArrayBuffer.slice()")}} {{non-standard_inline}}</dt> + <dd>Has the same functionality as {{jsxref("ArrayBuffer.prototype.slice()")}}.</dd> +</dl> + +<h2 id="Exemplo">Exemplo</h2> + +<p>In this example, we create a 8-byte buffer with a {{jsxref("Global_Objects/Int32Array", "Int32Array")}} view referring to the buffer:</p> + +<pre><code>var buffer = new ArrayBuffer(8); +var view = new Int32Array(buffer);</code></pre> + +<h2 id="Especificações">Especificações</h2> + +<table class="standard-table"> + <tbody> + <tr> + <th scope="col">Especificação</th> + <th scope="col">Status</th> + <th scope="col">Comentário</th> + </tr> + <tr> + <td>{{SpecName('Typed Array')}}</td> + <td>{{Spec2('Typed Array')}}</td> + <td>Substituído pelo ECMAScript 6</td> + </tr> + <tr> + <td>{{SpecName('ES6', '#sec-arraybuffer-constructor', 'ArrayBuffer')}}</td> + <td>{{Spec2('ES6')}}</td> + <td>Definição inicial no ECMA standard. Specified that <code>new</code> is required.</td> + </tr> + <tr> + <td>{{SpecName('ESDraft', '#sec-arraybuffer-constructor', 'ArrayBuffer')}}</td> + <td>{{Spec2('ESDraft')}}</td> + <td> </td> + </tr> + </tbody> +</table> + +<h2 id="Compatibilidade_entre_Navegadores">Compatibilidade entre Navegadores</h2> + +<div class="hidden"> +<p>The compatibility table on 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> +</div> + +<p>{{Compat("javascript.builtins.ArrayBuffer")}}</p> + +<h2 id="Compatibility_notes">Compatibility notes</h2> + +<p>Starting with ECMAScript 2015, <code>ArrayBuffer</code> constructors require to be constructed with a {{jsxref("Operators/new", "new")}} operator. Calling an <code>ArrayBuffer</code> constructor as a function without <code>new</code>, will throw a {{jsxref("TypeError")}} from now on.</p> + +<pre class="brush: js example-bad">var dv = ArrayBuffer(10); +// TypedError: calling a builtin ArrayBuffer constructor +// without new is forbidden</pre> + +<pre class="brush: js example-good">var dv = new ArrayBuffer(10);</pre> + +<h2 id="Veja_também">Veja também</h2> + +<ul> + <li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Typed_arrays">JavaScript typed arrays</a></li> + <li>{{jsxref("SharedArrayBuffer")}}</li> +</ul> |