diff options
Diffstat (limited to 'files/pt-pt/web/javascript/reference/statements/block/index.html')
| -rw-r--r-- | files/pt-pt/web/javascript/reference/statements/block/index.html | 117 |
1 files changed, 0 insertions, 117 deletions
diff --git a/files/pt-pt/web/javascript/reference/statements/block/index.html b/files/pt-pt/web/javascript/reference/statements/block/index.html deleted file mode 100644 index 4a6507702f..0000000000 --- a/files/pt-pt/web/javascript/reference/statements/block/index.html +++ /dev/null @@ -1,117 +0,0 @@ ---- -title: Bloco (block) -slug: Web/JavaScript/Reference/Statements/block -tags: - - Declaração - - Funcionalidade de Linguagem - - JavaScript - - Referencia -translation_of: Web/JavaScript/Reference/Statements/block -original_slug: Web/JavaScript/Reference/Extratos_e_declarações/bloco ---- -<div>Bloco {{jsSidebar("Statements")}}</div> - -<p>Uma <strong>declaralção bloco </strong>(ou <strong>declaração composto</strong> em outras linguagens) é utilizada para agrupar zero ou mais declarações. O bloco é delimitado por um par de chavetas (“chavetas { }”) e opcionalmente poderá ser {{jsxref("Statements/label", "labelled", "", 1)}}:</p> - -<div>{{EmbedInteractiveExample("pages/js/statement-block.html", "taller")}}</div> - - - -<h2 id="Sintaxe">Sintaxe</h2> - -<h3 id="Declaração_de_Bloco">Declaração de Bloco</h3> - -<pre class="syntaxbox">{ - <em>StatementList</em> -} -</pre> - -<h3 id="Declaração_de_Bloco_Etiquetado">Declaração de Bloco Etiquetado</h3> - -<pre class="syntaxbox"><em>LabelIdentifier</em>: { - <em>StatementList</em> -} -</pre> - -<dl> - <dt><code>StatementList</code></dt> - <dd>Statements grouped within the block statement.</dd> - <dt><code>LabelIdentifier</code></dt> - <dd>An optional {{jsxref("Statements/label", "label", "", 1)}} for visual identification or as a target for {{jsxref("Statements/break", "break")}}.</dd> -</dl> - -<h2 id="Descrição">Descrição</h2> - -<p>The block statement is often called <strong>compound statement</strong> in other languages. It allows you to use multiple statements where JavaScript expects only one statement. Combining statements into blocks is a common practice in JavaScript. The opposite behavior is possible using an <a href="/en-US/docs/Web/JavaScript/Reference/Statements/Empty">empty statement</a>, where you provide no statement, although one is required.</p> - -<p>Blocks are commonly used in association with {{jsxref("Statements/if...else", "if...else")}} and {{jsxref("Statements/for", "for")}} statements.</p> - -<h3 id="Block_Scoping_Rules">Block Scoping Rules</h3> - -<h4 id="With_var_or_function_declaration_in_non-strict_mode">With <code>var</code> or function declaration in non-strict mode</h4> - -<p>Variables declared with <code>var</code> or created by <a href="/en-US/docs/Web/JavaScript/Reference/Statements/function">function declarations</a> in non-strict mode <strong>do not</strong> have block scope. Variables introduced within a block are scoped to the containing function or script, and the effects of setting them persist beyond the block itself. In other words, block statements do not introduce a scope. For example:</p> - -<pre class="brush: js example-bad">var x = 1; -{ - var x = 2; -} -console.log(x); // logs 2 -</pre> - -<p>This logs 2 because the <code>var x</code> statement within the block is in the same scope as the <code>var x</code> statement before the block.</p> - -<p>In non-strict code, function declarations inside blocks behave strangely. Do not use them.</p> - -<h4 id="With_let_const_or_function_declaration_in_strict_mode">With <code>let</code>, <code>const</code> or function declaration in strict mode</h4> - -<p>By contrast, identifiers declared with {{jsxref("Statements/let", "let")}} and {{jsxref("Statements/const", "const")}} <strong>do have </strong>block scope:</p> - -<pre class="brush: js">let x = 1; -{ - let x = 2; -} -console.log(x); // logs 1</pre> - -<p>The <code>x = 2</code> is limited in scope to the block in which it was defined.</p> - -<p>The same is true of <code>const</code>:</p> - -<pre class="brush: js">const c = 1; -{ - const c = 2; -} -console.log(c); // logs 1 and does not throw SyntaxError...</pre> - -<p>Note that the block-scoped <code>const c = 2</code> <em>does not</em> throw a <code>SyntaxError: Identifier 'c' has already been declared</code> because it can be declared uniquely within the block.</p> - -<p>In <a href="/en-US/docs/Web/JavaScript/Reference/Strict_mode">strict mode</a>, starting with ES2015, functions inside blocks are scoped to that block. Prior to ES2015, block-level functions were forbidden in strict mode.</p> - -<h2 id="Especificações">Especificações</h2> - -<table class="standard-table"> - <thead> - <tr> - <th scope="col">Especificação</th> - </tr> - </thead> - <tbody> - <tr> - <td>{{SpecName('ESDraft', '#sec-block', 'Block statement')}}</td> - </tr> - </tbody> -</table> - -<h2 id="Compatibilidade_de_navegador">Compatibilidade de navegador</h2> - - - -<p>{{Compat("javascript.statements.block")}}</p> - -<h2 id="Consulte_também">Consulte também</h2> - -<ul> - <li>{{jsxref("Statements/while", "while")}}</li> - <li>{{jsxref("Statements/if...else", "if...else")}}</li> - <li>{{jsxref("Statements/let", "let")}}</li> -</ul> |