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+---
+title: Object.assign()
+slug: Web/JavaScript/Reference/Global_Objects/Object/assign
+translation_of: Web/JavaScript/Reference/Global_Objects/Object/assign
+---
+<p>{{JSRef}}</p>
+
+<p dir="rtl">מתודת <span class="seoSummary"><strong><code>Object.assign</code> מעתיקה אובייקט על שלל </strong>{{jsxref("Object/propertyIsEnumerable", "מאפייניו", "", 1)} {{jsxref("Object/hasOwnProperty", "הקיימים", "", 1)}} לאובייקט אחר וממזגת אותם ביחד. המתודה מחזירה את האובייקט שאליו העתקנו את התכונות החדשות. </span></p>
+
+<div dir="rtl">תחביר</div>
+
+<pre class="syntaxbox notranslate">Object.assign(<var>target</var>, ...<var>sources</var>)</pre>
+
+<h3 dir="rtl" id="פרמטרים">פרמטרים</h3>
+
+<dl>
+ <dt dir="rtl"><code><var>target - אובייקט היעד</var></code></dt>
+ <dd dir="rtl">אובייקט היעד- האובייקט שאליו אנחנו מעתיקים את כל המאפיינים של האובייקט המקורי, כאשר הוא מחזיר את האובייקט אחרי המיזוג.</dd>
+ <dt dir="rtl"><code><var>sources - אובייקט המקור</var></code></dt>
+ <dd></dd>
+</dl>
+
+<dl>
+ <dd dir="rtl">אובייקט המקור - האובייקט מכיל את המאפיינים שאנחנו רוצים להעתיק לאובייקט נוסף. </dd>
+</dl>
+
+<h3 dir="rtl" id="Return_value_-_הנתון_התוצאה">Return value - הנתון התוצאה</h3>
+
+<p dir="rtl">The target object - האובייקט שאליו העתקנו את התכונות של האובייקט המקורי.</p>
+
+<h2 dir="rtl" id="תיאור">תיאור</h2>
+
+<p dir="rtl">מאפיינים באובייקט היעד ישוכתבו או ידרסו ע"י המאפיינים של אובייקט המקור אם הם חולקים את אותו ה-{{jsxref("Object/keys", "key", "", 1)}}. מאפיינים חדשים שיוגדו על מאפיינים משותפים (properties) בהמשך ידרסו גם באובייקט היעד וגם באופייקט המקור.</p>
+
+<p dir="rtl"></p>
+
+<p>The <code>Object.assign()</code> method only copies <em>enumerable</em> and <em>own</em> properties from a source object to a target object. It uses <code>[[Get]]</code> on the source and <code>[[Set]]</code> on the target, so it will invoke <a href="/en-US/docs/Web/JavaScript/Reference/Functions/get">getters</a> and <a href="/en-US/docs/Web/JavaScript/Reference/Functions/set">setters</a>. Therefore it <em>assigns</em> properties, versus copying or defining new properties. This may make it unsuitable for merging new properties into a prototype if the merge sources contain getters.</p>
+
+<p>For copying property definitions (including their enumerability) into prototypes, use {{jsxref("Object.getOwnPropertyDescriptor()")}} and {{jsxref("Object.defineProperty()")}} instead.</p>
+
+<p>Both {{jsxref("String")}} and {{jsxref("Symbol")}} properties are copied.</p>
+
+<p>In case of an error, for example if a property is non-writable, a {{jsxref("TypeError")}} is raised, and the <code><var>target</var></code> object is changed if any properties are added before the error is raised.</p>
+
+<div class="blockIndicator note">
+<p><strong>Note:</strong> <code>Object.assign()</code> does not throw on {{jsxref("null")}} or {{jsxref("undefined")}} sources.</p>
+</div>
+
+<h2 id="Polyfill">Polyfill</h2>
+
+<p>This <a href="/en-US/docs/Glossary/Polyfill">polyfill</a> doesn't support symbol properties, since ES5 doesn't have symbols anyway:</p>
+
+<pre class="brush: js notranslate">if (typeof Object.assign !== 'function') {
+ // Must be writable: true, enumerable: false, configurable: true
+ Object.defineProperty(Object, "assign", {
+ value: function assign(target, varArgs) { // .length of function is 2
+ 'use strict';
+ if (target === null || target === undefined) {
+ throw new TypeError('Cannot convert undefined or null to object');
+ }
+
+ var to = Object(target);
+
+ for (var index = 1; index &lt; arguments.length; index++) {
+ var nextSource = arguments[index];
+
+ if (nextSource !== null &amp;&amp; nextSource !== undefined) {
+ for (var nextKey in nextSource) {
+ // Avoid bugs when hasOwnProperty is shadowed
+ if (Object.prototype.hasOwnProperty.call(nextSource, nextKey)) {
+ to[nextKey] = nextSource[nextKey];
+ }
+ }
+ }
+ }
+ return to;
+ },
+ writable: true,
+ configurable: true
+ });
+}
+</pre>
+
+<h2 id="Examples">Examples</h2>
+
+<h3 id="Cloning_an_object">Cloning an object</h3>
+
+<pre class="brush: js notranslate">const obj = { a: 1 };
+const copy = Object.assign({}, obj);
+console.log(copy); // { a: 1 }
+</pre>
+
+<h3 id="Deep_Clone" name="Deep_Clone">Warning for Deep Clone</h3>
+
+<p>For deep cloning, we need to use alternatives, because <code>Object.assign()</code> copies property values.</p>
+
+<p>If the source value is a reference to an object, it only copies the reference value.</p>
+
+<pre class="brush: js notranslate">function test() {
+ 'use strict';
+
+ let obj1 = { a: 0 , b: { c: 0}};
+ let obj2 = Object.assign({}, obj1);
+ console.log(JSON.stringify(obj2)); // { "a": 0, "b": { "c": 0}}
+
+ obj1.a = 1;
+ console.log(JSON.stringify(obj1)); // { "a": 1, "b": { "c": 0}}
+ console.log(JSON.stringify(obj2)); // { "a": 0, "b": { "c": 0}}
+
+ obj2.a = 2;
+ console.log(JSON.stringify(obj1)); // { "a": 1, "b": { "c": 0}}
+ console.log(JSON.stringify(obj2)); // { "a": 2, "b": { "c": 0}}
+
+ obj2.b.c = 3;
+ console.log(JSON.stringify(obj1)); // { "a": 1, "b": { "c": 3}}
+ console.log(JSON.stringify(obj2)); // { "a": 2, "b": { "c": 3}}
+
+ // Deep Clone
+ obj1 = { a: 0 , b: { c: 0}};
+ let obj3 = JSON.parse(JSON.stringify(obj1));
+ obj1.a = 4;
+ obj1.b.c = 4;
+ console.log(JSON.stringify(obj3)); // { "a": 0, "b": { "c": 0}}
+}
+
+test();</pre>
+
+<h3 id="Merging_objects">Merging objects</h3>
+
+<pre class="brush: js notranslate">const o1 = { a: 1 };
+const o2 = { b: 2 };
+const o3 = { c: 3 };
+
+const obj = Object.assign(o1, o2, o3);
+console.log(obj); // { a: 1, b: 2, c: 3 }
+console.log(o1); // { a: 1, b: 2, c: 3 }, target object itself is changed.</pre>
+
+<h3 id="Merging_objects_with_same_properties">Merging objects with same properties</h3>
+
+<pre class="brush: js notranslate">const o1 = { a: 1, b: 1, c: 1 };
+const o2 = { b: 2, c: 2 };
+const o3 = { c: 3 };
+
+const obj = Object.assign({}, o1, o2, o3);
+console.log(obj); // { a: 1, b: 2, c: 3 }</pre>
+
+<p>The properties are overwritten by other objects that have the same properties later in the parameters order.</p>
+
+<h3 id="Copying_symbol-typed_properties">Copying symbol-typed properties</h3>
+
+<pre class="brush: js notranslate">const o1 = { a: 1 };
+const o2 = { [Symbol('foo')]: 2 };
+
+const obj = Object.assign({}, o1, o2);
+console.log(obj); // { a : 1, [Symbol("foo")]: 2 } (cf. bug 1207182 on Firefox)
+Object.getOwnPropertySymbols(obj); // [Symbol(foo)]
+</pre>
+
+<h3 id="Properties_on_the_prototype_chain_and_non-enumerable_properties_cannot_be_copied">Properties on the prototype chain and non-enumerable properties cannot be copied</h3>
+
+<pre class="brush: js notranslate">const obj = Object.create({ foo: 1 }, { // foo is on obj's prototype chain.
+ bar: {
+ value: 2 // bar is a non-enumerable property.
+ },
+ baz: {
+ value: 3,
+ enumerable: true // baz is an own enumerable property.
+ }
+});
+
+const copy = Object.assign({}, obj);
+console.log(copy); // { baz: 3 }
+</pre>
+
+<h3 id="Primitives_will_be_wrapped_to_objects">Primitives will be wrapped to objects</h3>
+
+<pre class="brush: js notranslate">const v1 = 'abc';
+const v2 = true;
+const v3 = 10;
+const v4 = Symbol('foo');
+
+const obj = Object.assign({}, v1, null, v2, undefined, v3, v4);
+// Primitives will be wrapped, null and undefined will be ignored.
+// Note, only string wrappers can have own enumerable properties.
+console.log(obj); // { "0": "a", "1": "b", "2": "c" }
+</pre>
+
+<h3 id="Exceptions_will_interrupt_the_ongoing_copying_task">Exceptions will interrupt the ongoing copying task</h3>
+
+<pre class="brush: js notranslate">const target = Object.defineProperty({}, 'foo', {
+ value: 1,
+ writable: false
+}); // target.foo is a read-only property
+
+Object.assign(target, { bar: 2 }, { foo2: 3, foo: 3, foo3: 3 }, { baz: 4 });
+// TypeError: "foo" is read-only
+// The Exception is thrown when assigning target.foo
+
+console.log(target.bar); // 2, the first source was copied successfully.
+console.log(target.foo2); // 3, the first property of the second source was copied successfully.
+console.log(target.foo); // 1, exception is thrown here.
+console.log(target.foo3); // undefined, assign method has finished, foo3 will not be copied.
+console.log(target.baz); // undefined, the third source will not be copied either.
+</pre>
+
+<h3 id="Copying_accessors">Copying accessors</h3>
+
+<pre class="brush: js notranslate">const obj = {
+ foo: 1,
+ get bar() {
+ return 2;
+ }
+};
+
+let copy = Object.assign({}, obj);
+console.log(copy);
+// { foo: 1, bar: 2 }
+// The value of copy.bar is obj.bar's getter's return value.
+
+// This is an assign function that copies full descriptors
+function completeAssign(target, ...sources) {
+ sources.forEach(source =&gt; {
+ let descriptors = Object.keys(source).reduce((descriptors, key) =&gt; {
+ descriptors[key] = Object.getOwnPropertyDescriptor(source, key);
+ return descriptors;
+ }, {});
+
+  // By default, Object.assign copies enumerable Symbols, too
+ Object.getOwnPropertySymbols(source).forEach(sym =&gt; {
+ let descriptor = Object.getOwnPropertyDescriptor(source, sym);
+ if (descriptor.enumerable) {
+ descriptors[sym] = descriptor;
+ }
+ });
+ Object.defineProperties(target, descriptors);
+ });
+ return target;
+}
+
+copy = completeAssign({}, obj);
+console.log(copy);
+// { foo:1, get bar() { return 2 } }
+</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-object.assign', 'Object.assign')}}</td>
+ </tr>
+ </tbody>
+</table>
+
+<h2 id="Browser_compatibility">Browser compatibility</h2>
+
+
+
+<p>{{Compat("javascript.builtins.Object.assign")}}</p>
+
+<h2 id="See_also">See also</h2>
+
+<ul>
+ <li>{{jsxref("Object.defineProperties()")}}</li>
+ <li><a href="/en-US/docs/Web/JavaScript/Enumerability_and_ownership_of_properties">Enumerability and ownership of properties</a></li>
+ <li><a href="/en-US/docs/Web/JavaScript/Reference/Operators/Spread_syntax#Spread_in_object_literals">Spread in object literals</a></li>
+</ul>