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الدالة push()
هي دالة تضيف عنصر أو عناصر إلى نهاية المصفوفة مع إعادة طول المصفوفة الجديد
Syntax
arr.push(element1, ..., elementN)
Parameters
elementN
- تضاف العناصر إلى نهاية المصفوفة
قيمة الإرجاع
The new length
property of the object upon which the method was called.
وصف
دالة push
هي دالة تقوم بإلحاق القيم للمصفوفة
push
is intentionally generic. This method can be used with call()
or apply()
on objects resembling arrays. The push
method relies on a length
property to determine where to start inserting the given values. If the length
property cannot be converted into a number, the index used is 0. This includes the possibility of length
being nonexistent, in which case length
will also be created.
The only native, array-like objects are strings, although they are not suitable in applications of this method, as strings are immutable.
أمثلة
إضافة عناصر إلى مجموعة
التعليمة البرمجية التالية : تقوم بإنشاء مصفوفة (sports ) تحتوي على عنصرين، ثم يتم إلحاق عنصرين إليها.
يحتوي المتغير (total)على طول الجديد للمصفوفة.
var sports = ['soccer', 'baseball']; var total = sports.push('football', 'swimming'); console.log(sports); // ['soccer', 'baseball', 'football', 'swimming'] console.log(total); // 4
دمج مصفوفتين
هذا المثال يستخدم apply()
لإلحاق كل عناصر المصفوفة الثانية بالمصفوفة الأولى
var vegetables = ['parsnip', 'potato']; var moreVegs = ['celery', 'beetroot']; // دمج المصفوفة الثانية بالأولى //كانه كتب //vegetables.push('celery', 'beetroot'); Array.prototype.push.apply(vegetables, moreVegs); console.log(vegetables); // ['parsnip', 'potato', 'celery', 'beetroot']
استخدام كائن بطريقة تشبه المصفوفة
As mentioned above, push
is intentionally generic, and we can use that to our advantage. Array.prototype.push
can work on an object just fine, as this example shows. Note that we don't create an array to store a collection of objects. Instead, we store the collection on the object itself and use call
on Array.prototype.push
to trick the method into thinking we are dealing with an array, and it just works, thanks to the way JavaScript allows us to establish the execution context however we please.
var obj = { length: 0, addElem: function addElem (elem) { // obj.length is automatically incremented every time an element is added. [].push.call(this, elem); } }; // Let's add some empty objects just to illustrate. obj.addElem({}); obj.addElem({}); console.log(obj.length); // → 2
لاحظ أنه على الرغم من أن الكائن ليس مصفوفة،فإن دالة push
نجحت في تزايد خاصية طول الكائن كما لو أننا نتعامل مع مصفوفة عادية
Specifications
Specification | Status | Comment |
---|---|---|
ECMAScript 3rd Edition (ECMA-262) | Standard | Initial definition. Implemented in JavaScript 1.2. |
ECMAScript 5.1 (ECMA-262) The definition of 'Array.prototype.push' in that specification. |
Standard | |
ECMAScript 2015 (6th Edition, ECMA-262) The definition of 'Array.prototype.push' in that specification. |
Standard | |
ECMAScript 2017 Draft (ECMA-262) The definition of 'Array.prototype.push' in that specification. |
Draft |
Browser compatibility
Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari |
---|---|---|---|---|---|
Basic support | 1.0 | 1.0 (1.7 or earlier) | 5.5 | (Yes) | (Yes) |
Feature | Android | Chrome for Android | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile |
---|---|---|---|---|---|---|
Basic support | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) |