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+---
+title: Enumerabilitat i pertanyença de les propietats
+slug: Web/JavaScript/Enumerability_and_ownership_of_properties
+translation_of: Web/JavaScript/Enumerability_and_ownership_of_properties
+---
+<div>{{JsSidebar("More")}}</div>
+
+<p>Les propietats enumerables són aquelles que es poden iterar en un <a href="/en-US/docs/JavaScript/Reference/Statements/for...in">bucle for..in</a>. La pertanyença de les propietats és determinada pel fet de si la propietat pertany directament a l'objecte en comptes de la seva cadena de prototipus. Les propietats d'un objecte també poden ser contades per a obtenir el nombre de propietats. Hi ha diverses formes de detectar, iterar/enumerar i obtindre les propietats d'un objecte. Es pot veure a la taula quines es poden emprar en cada cas. A continuació trobareu un bocí de codi d'exemple on es mostra com otenir les categories no trobades.</p>
+
+<table>
+ <caption>Enumerabilitat i pertanyença de propietats - mètodes de detecció,  obtenció i iteració</caption>
+ <tbody>
+ <tr>
+ <th>Funcionalitat</th>
+ <th>Pertanyença a l'objecte</th>
+ <th>Pertanyença a l'objecte o la seva cadena de prototipus</th>
+ <th>Pertanyença només a la cadena de prototipus</th>
+ </tr>
+ <tr>
+ <td>Detecció</td>
+ <td>
+ <table>
+ <thead>
+ <tr>
+ <th scope="col">Enumerable</th>
+ <th scope="col">No enumerable</th>
+ <th scope="col">Enumerable i No enumerable</th>
+ </tr>
+ </thead>
+ <tbody>
+ <tr>
+ <td><code><a href="/en-US/docs/JavaScript/Reference/Global_Objects/Object/propertyIsEnumerable" title="/en-US/docs/JavaScript/Reference/Global_Objects/Object/propertyIsEnumerable">propertyIsEnumerable</a></code></td>
+ <td><code><a href="/en-US/docs/JavaScript/Reference/Global_Objects/Object/hasOwnProperty" title="/en-US/docs/JavaScript/Reference/Global_Objects/Object/hasOwnProperty">hasOwnProperty</a></code> i no <code><a href="/en-US/docs/JavaScript/Reference/Global_Objects/Object/propertyIsEnumerable" title="/en-US/docs/JavaScript/Reference/Global_Objects/Object/propertyIsEnumerable">propertyIsEnumerable</a></code></td>
+ <td><code><a href="/en-US/docs/JavaScript/Reference/Global_Objects/Object/hasOwnProperty" title="/en-US/docs/JavaScript/Reference/Global_Objects/Object/hasOwnProperty">hasOwnProperty</a></code></td>
+ </tr>
+ </tbody>
+ </table>
+ </td>
+ <td>No disponible sense escriure més codi</td>
+ <td>No disponible sense escriure més codi</td>
+ </tr>
+ <tr>
+ <td>Obtenció</td>
+ <td>
+ <table>
+ <thead>
+ <tr>
+ <th scope="col">Enumerable</th>
+ <th scope="col">No enumerable</th>
+ <th scope="col">Enumerable i No enumerable</th>
+ </tr>
+ </thead>
+ <tbody>
+ <tr>
+ <td><code><a href="/en-US/docs/JavaScript/Reference/Global_Objects/Object/keys" title="/en-US/docs/JavaScript/Reference/Global_Objects/Object/keys">Object.keys</a></code></td>
+ <td><code><a href="/en-US/docs/JavaScript/Reference/Global_Objects/Object/getOwnPropertyNames" title="/en-US/docs/JavaScript/Reference/Global_Objects/Object/getOwnPropertyNames">getOwnPropertyNames</a></code> filtrat per a incloure propietats si no se li passa<code> <a href="/en-US/docs/JavaScript/Reference/Global_Objects/Object/propertyIsEnumerable" title="/en-US/docs/JavaScript/Reference/Global_Objects/Object/propertyIsEnumerable">propertyIsEnumerable</a></code></td>
+ <td><code><a href="/en-US/docs/JavaScript/Reference/Global_Objects/Object/getOwnPropertyNames" title="/en-US/docs/JavaScript/Reference/Global_Objects/Object/getOwnPropertyNames">getOwnPropertyNames</a></code></td>
+ </tr>
+ </tbody>
+ </table>
+ </td>
+ <td>No disponible sense escriure més codi</td>
+ <td>No disponible sense escriure més codi</td>
+ </tr>
+ <tr>
+ <td>Iteració</td>
+ <td>
+ <table>
+ <thead>
+ <tr>
+ <th scope="col">Enumerable</th>
+ <th scope="col">No enumerable</th>
+ <th scope="col">Enumerable i No enumerable</th>
+ </tr>
+ </thead>
+ <tbody>
+ <tr>
+ <td>Iterar sobre <code><a href="/en-US/docs/JavaScript/Reference/Global_Objects/Object/keys" title="/en-US/docs/JavaScript/Reference/Global_Objects/Object/keys">Object.keys</a></code></td>
+ <td>Iterar sobre <code><a href="/en-US/docs/JavaScript/Reference/Global_Objects/Object/getOwnPropertyNames" title="/en-US/docs/JavaScript/Reference/Global_Objects/Object/getOwnPropertyNames">getOwnPropertyNames</a> </code>filtrat per a incloure propietats si no se li passa<code> <a href="/en-US/docs/JavaScript/Reference/Global_Objects/Object/propertyIsEnumerable" title="/en-US/docs/JavaScript/Reference/Global_Objects/Object/propertyIsEnumerable">propertyIsEnumerable</a></code></td>
+ <td>Iterar sobre <code><a href="/en-US/docs/JavaScript/Reference/Global_Objects/Object/getOwnPropertyNames" title="/en-US/docs/JavaScript/Reference/Global_Objects/Object/getOwnPropertyNames">getOwnPropertyNames</a></code></td>
+ </tr>
+ </tbody>
+ </table>
+ </td>
+ <td>
+ <table>
+ <thead>
+ <tr>
+ <th scope="col">Enumerable</th>
+ <th scope="col">No enumerable</th>
+ <th scope="col">Enumerable i No enumerable</th>
+ </tr>
+ </thead>
+ <tbody>
+ <tr>
+ <td><code><a href="/en-US/docs/JavaScript/Reference/Statements/for...in" title="/en-US/docs/JavaScript/Reference/Statements/for...in">for..in</a></code></td>
+ <td>No disponible sense escriure més codi</td>
+ <td>No disponible sense escriure més codi</td>
+ </tr>
+ </tbody>
+ </table>
+ </td>
+ <td>No disponible sense escriure més codi</td>
+ </tr>
+ </tbody>
+</table>
+
+<h2 id="Obtindre_propietats_per_enumerabilitatpertanyença">Obtindre propietats per enumerabilitat/pertanyença</h2>
+
+<p>Cal recalcar que aquest no és l'algorisme més eficient per a tots els casos, però és útil per a una demostració ràpida.</p>
+
+<ul>
+ <li>La detecció es pot aconseguir mitjançant <code>SimplePropertyRetriever.theGetMethodYouWant(obj).indexOf(prop) &gt; -1</code></li>
+ <li>La iteració es pot aconseguir mitjançant <code>SimplePropertyRetriever.theGetMethodYouWant(obj).forEach(function (value, prop) {});</code> (<code>o bé usant filter()</code>, <code>map()</code>, etc.)</li>
+</ul>
+
+<pre class="brush: js">var SimplePropertyRetriever = {
+ getOwnEnumerables: function (obj) {
+ return this._getPropertyNames(obj, true, false, this._enumerable);
+ // O es podria utilitzar for..in filtrat amb hasOwnProperty o bé simplement això: return Object.keys(obj);
+ },
+ getOwnNonenumerables: function (obj) {
+ return this._getPropertyNames(obj, true, false, this._notEnumerable);
+ },
+ getOwnEnumerablesAndNonenumerables: function (obj) {
+ return this._getPropertyNames(obj, true, false, this._enumerableAndNotEnumerable);
+ // O bé simplement utilitzar: return Object.getOwnPropertyNames(obj);
+ },
+ getPrototypeEnumerables: function (obj) {
+ return this._getPropertyNames(obj, false, true, this._enumerable);
+ },
+ getPrototypeNonenumerables: function (obj) {
+ return this._getPropertyNames(obj, false, true, this._notEnumerable);
+ },
+ getPrototypeEnumerablesAndNonenumerables: function (obj) {
+ return this._getPropertyNames(obj, false, true, this._enumerableAndNotEnumerable);
+ },
+ getOwnAndPrototypeEnumerables: function (obj) {
+ return this._getPropertyNames(obj, true, true, this._enumerable);
+ // O bé es podria utilitzar un for..in sense filtrar
+ },
+ getOwnAndPrototypeNonenumerables: function (obj) {
+ return this._getPropertyNames(obj, true, true, this._notEnumerable);
+ },
+ getOwnAndPrototypeEnumerablesAndNonenumerables: function (obj) {
+ return this._getPropertyNames(obj, true, true, this._enumerableAndNotEnumerable);
+ },
+ // Private static property checker callbacks
+ _enumerable : function (obj, prop) {
+ return obj.propertyIsEnumerable(prop);
+ },
+ _notEnumerable : function (obj, prop) {
+ return !obj.propertyIsEnumerable(prop);
+ },
+ _enumerableAndNotEnumerable : function (obj, prop) {
+ return true;
+ },
+ // Inspirat per http://stackoverflow.com/a/8024294/271577
+ _getPropertyNames : function getAllPropertyNames(obj, iterateSelfBool, iteratePrototypeBool, includePropCb) {
+ var props = [];
+
+ do {
+ if (iterateSelfBool) {
+ Object.getOwnPropertyNames(obj).forEach(function (prop) {
+ if (props.indexOf(prop) === -1 &amp;&amp; includePropCb(obj, prop)) {
+ props.push(prop);
+ }
+ });
+ }
+ if (!iteratePrototypeBool) {
+ break;
+ }
+ iterateSelfBool = true;
+ } while (obj = Object.getPrototypeOf(obj));
+
+ return props;
+ }
+};</pre>
+
+<h2 id="Taula_de_detecció">Taula de detecció</h2>
+
+<table>
+ <thead>
+ <tr>
+ <th scope="row"> </th>
+ <th scope="col"><code>in</code></th>
+ <th scope="col"><code>for..in</code></th>
+ <th scope="col"><code>hasOwnProperty</code></th>
+ <th scope="col"><code>propertyIsEnumerable</code></th>
+ <th scope="col"><code>in Object.keys</code></th>
+ <th scope="col"><code>in Object.getOwnPropertyNames</code></th>
+ </tr>
+ </thead>
+ <tbody>
+ <tr>
+ <th scope="row">Enumerable</th>
+ <td>true</td>
+ <td>true</td>
+ <td>true</td>
+ <td>true</td>
+ <td>true</td>
+ <td>true</td>
+ </tr>
+ <tr>
+ <th scope="row">No enumerable</th>
+ <td>true</td>
+ <td>false</td>
+ <td>true</td>
+ <td>false</td>
+ <td>false</td>
+ <td>true</td>
+ </tr>
+ <tr>
+ <th scope="row">Enumerable heredat</th>
+ <td>true</td>
+ <td>true</td>
+ <td>false</td>
+ <td>false</td>
+ <td>false</td>
+ <td>false</td>
+ </tr>
+ <tr>
+ <th scope="row">No enumerable heredat</th>
+ <td>true</td>
+ <td>false</td>
+ <td>false</td>
+ <td>false</td>
+ <td>false</td>
+ <td>false</td>
+ </tr>
+ </tbody>
+</table>
+
+<h2 id="Vegeu_també">Vegeu també</h2>
+
+<ul>
+ <li><code><a href="/en-US/docs/JavaScript/Reference/Operators/in" title="/en-US/docs/JavaScript/Reference/Operators/in">in</a></code></li>
+ <li><code><a href="/en-US/docs/JavaScript/Reference/Statements/for...in" title="/en-US/docs/JavaScript/Reference/Statements/for...in">for..in</a></code></li>
+ <li><code><a href="/en-US/docs/JavaScript/Reference/Global_Objects/Object/hasOwnProperty" title="/en-US/docs/JavaScript/Reference/Global_Objects/Object/hasOwnProperty">hasOwnProperty</a></code></li>
+ <li><code><a href="/en-US/docs/JavaScript/Reference/Global_Objects/Object/propertyIsEnumerable" title="/en-US/docs/JavaScript/Reference/Global_Objects/Object/propertyIsEnumerable">propertyIsEnumerable</a></code></li>
+ <li><code><a href="/en-US/docs/JavaScript/Reference/Global_Objects/Object/getOwnPropertyNames" title="/en-US/docs/JavaScript/Reference/Global_Objects/Object/getOwnPropertyNames">getOwnPropertyNames</a></code></li>
+ <li><code><a href="/en-US/docs/JavaScript/Reference/Global_Objects/Object/keys" title="/en-US/docs/JavaScript/Reference/Global_Objects/Object/keys">Object.keys</a></code></li>
+</ul>