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author | Peter Bengtsson <mail@peterbe.com> | 2020-12-08 14:42:17 -0500 |
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committer | Peter Bengtsson <mail@peterbe.com> | 2020-12-08 14:42:17 -0500 |
commit | da78a9e329e272dedb2400b79a3bdeebff387d47 (patch) | |
tree | e6ef8aa7c43556f55ddfe031a01cf0a8fa271bfe /files/it/web/javascript/reference/global_objects/function/length | |
parent | 1109132f09d75da9a28b649c7677bb6ce07c40c0 (diff) | |
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Diffstat (limited to 'files/it/web/javascript/reference/global_objects/function/length')
-rw-r--r-- | files/it/web/javascript/reference/global_objects/function/length/index.html | 87 |
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diff --git a/files/it/web/javascript/reference/global_objects/function/length/index.html b/files/it/web/javascript/reference/global_objects/function/length/index.html new file mode 100644 index 0000000000..6e305fb3ed --- /dev/null +++ b/files/it/web/javascript/reference/global_objects/function/length/index.html @@ -0,0 +1,87 @@ +--- +title: Function.length +slug: Web/JavaScript/Reference/Global_Objects/Function/length +translation_of: Web/JavaScript/Reference/Global_Objects/Function/length +--- +<div>{{JSRef}}</div> + +<p>La proprietà <code><strong>length</strong></code> indica il numero di parametri che la funzione si aspetta di ricevere.</p> + +<p>{{EmbedInteractiveExample("pages/js/function-length.html")}}</p> + + + +<div>{{js_property_attributes(0,0,1)}}</div> + +<h2 id="Description">Description</h2> + +<p><code>length</code> è una proprietà di un oggetto {{jsxref("Function")}} che indica quanti argomenti la funzione si aspetta, cioè il numero di parametri formali. Questo numero esclude il {{jsxref("rest_parameters", "rest parameter", "", 1)}} e include solo i parametri prima del primo con un valore predefinito. Al contrario, {{jsxref("Functions_and_function_scope/arguments/length", "arguments.length")}} è locale a una funzione e fornisce il numero di argomenti effettivamente passati alla funzione.</p> + +<h3 id="Data_property_of_the_Function_constructor">Data property of the Function constructor</h3> + +<p>Il costruttore {{jsxref("Function")}} è esso stesso un oggetto {{jsxref("Function")}}. La sua proprietà <code>length</code> ha valore 1. Gli attributi delle proprietà sono: Writable: <code>false</code>, Enumerable: <code>false</code>, Configurable: <code>false</code>.</p> + +<h3 id="Property_of_the_Function_prototype_object">Property of the Function prototype object</h3> + +<p>La proprietà <code>length</code> del prototype di un oggetto {{jsxref("Function")}} ha valore 0.</p> + +<h2 id="Examples">Examples</h2> + +<pre class="brush: js">console.log(Function.length); /* 1 */ + +console.log((function() {}).length); /* 0 */ +console.log((function(a) {}).length); /* 1 */ +console.log((function(a, b) {}).length); /* 2 etc. */ + +console.log((function(...args) {}).length); +// 0, rest parameter is not counted + +console.log((function(a, b = 1, c) {}).length); +// 1, only parameters before the first one with +// a default value is counted</pre> + +<h2 id="Specifications">Specifications</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('ES1')}}</td> + <td>{{Spec2('ES1')}}</td> + <td>Definizione iniziale. Implementata in JavaScript 1.1.</td> + </tr> + <tr> + <td>{{SpecName('ES5.1', '#sec-15.3.5.1', 'Function.length')}}</td> + <td>{{Spec2('ES5.1')}}</td> + <td></td> + </tr> + <tr> + <td>{{SpecName('ES6', '#sec-function-instances-length', 'Function.length')}}</td> + <td>{{Spec2('ES6')}}</td> + <td>Gli attributi <font face="consolas, Liberation Mono, courier, monospace"><span style="background-color: rgba(220, 220, 220, 0.5);">configurabili</span></font> di queste proprietà diventano <code>true</code>.</td> + </tr> + <tr> + <td>{{SpecName('ESDraft', '#sec-function-instances-length', 'Function.length')}}</td> + <td>{{Spec2('ESDraft')}}</td> + <td></td> + </tr> + </tbody> +</table> + +<h2 id="Browser_compatibility">Browser compatibility</h2> + +<div> + + +<p>{{Compat("javascript.builtins.Function.length")}}</p> +</div> + +<h2 id="See_also">See also</h2> + +<ul> + <li>{{jsxref("Function")}}</li> +</ul> |