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Array Object (JavaScript)

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Provides support for creation of arrays of any data type.

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arrayObj = new Array()arrayObj = new Array([size])arrayObj = new Array([element0[, element1[, ...[, elementN]]]])

Parameters

arrayObj: Required. The variable name to which the Array object is assigned.
size: Optional. The size of the array. As arrays are zero-based, created elements will have indexes from zero to size -1.
element0,...,elementN: Optional. The elements to place in the array. This creates an array with n + 1 elements, and a length of n + 1. Using this syntax, you must supply more than one element.

Remarks

After an array is created, you can access the individual elements of the array by using [ ] notation, for example:

JavaScript

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var my_array = new Array();
for (i = 0; i < 10; i++) {
    my_array[i] = i;
}
x = my_array[4];

Since arrays in JavaScript are zero-based, the last statement in the preceding example accesses the fifth element of the array. That element contains the value 4.

If only one argument is passed to the Array constructor, and the argument is a number, it must be an unsigned 32-bit integer (< approximately four billion). That value then becomes the size of the array. If the value is a number, but is less than zero or is not an integer, a run-time error occurs.

If a single value is passed to the Array constructor, and it is not a number, the length property is set to 1, and the value of the only element becomes the single, passed-in argument.

Notice that JavaScript arrays are sparse arrays, that is, although you can allocate an array with many elements, only the elements that actually contain data exist. This reduces the amount of memory used by the array.

Requirements

The Array object was introduced in

Supported in the following document modes: Quirks, Internet Explorer 6 standards, Internet Explorer 7 standards, Internet Explorer 8 standards, Internet Explorer 9 standards, Internet Explorer 10 standards. Also supported in Metro style apps. See Version Information.

. Some members in the following lists were introduced in later versions.

Properties

The following table lists the properties of the Array object.

Property	Description
constructor Property	Specifies the function that creates an object.
length Property (Array)	Returns an integer value that is one higher than the highest element defined in an array.
prototype Property	Returns a reference to the prototype for a class of objects.

Functions

The following table describes the function of the Array object.

Function	Description
Array.isArray Function	Returns a Boolean value that indicates whether an object is an array.

Methods

The following table lists the methods of the Array object.

Method	Description
concat Method (Array)	Returns a new array consisting of a combination of two arrays.
every Method	Checks whether a defined callback function returns true for all elements in an array.
filter Method	Calls a defined callback function on each element of an array, and returns an array of values for which the callback function returns true.
forEach Method	Calls a defined callback function for each element in an array.
hasOwnProperty Method	Returns a Boolean value that indicates whether an object has a property with the specified name.
indexOf Method (Array)	Returns the index of the first occurrence of a value in an array.
isPrototypeOf Method	Returns a Boolean value that indicates whether an object exists in another object's prototype chain.
join Method	Returns a String object consisting of all the elements of an array concatenated together.
lastIndexOf Method (Array)	Returns the index of the last occurrence of a specified value in an array.
map Method	Calls a defined callback function on each element of an array, and returns an array that contains the results.
pop Method	Removes the last element from an array and returns it.
propertyIsEnumerable Method	Returns a Boolean value that indicates whether a specified property is part of an object and whether it is enumerable.
push Method	Appends new elements to an array, and returns the new length of the array.
reduce Method	Accumulates a single result by calling a defined callback function for all elements in an array. The return value of the callback function is the accumulated result, and is provided as an argument in the next call to the callback function.
reduceRight Method	Accumulates a single result by calling a defined callback function for all elements in an array, in descending order. The return value of the callback function is the accumulated result, and is provided as an argument in the next call to the callback function.
reverse Method	Returns an Array object with the elements reversed.
shift Method	Removes the first element from an array and returns it.
slice Method (Array)	Returns a section of an array.
some Method	Checks whether a defined callback function returns true for any element of an array.
sort Method	Returns an Array object with the elements sorted.
splice Method	Removes elements from an array and, if necessary, inserts new elements in their place, returning the deleted elements.
toLocaleString Method	Returns a string using the current locale.
toString Method	Returns a string representation of an object.
unshift Method	Inserts new elements at the start of an array.
valueOf Method	Returns the primitive value of the specified object.

Reference

JavaScript Objects

new Operator (JavaScript)

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