Array() constructor
Baseline Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
The Array()
constructor creates Array
objects.
Syntax
new Array()
new Array(element1)
new Array(element1, element2)
new Array(element1, element2, /* …, */ elementN)
new Array(arrayLength)
Array()
Array(element1)
Array(element1, element2)
Array(element1, element2, /* …, */ elementN)
Array(arrayLength)
Note: Array()
can be called with or without new
. Both create a new Array
instance.
Parameters
element1
, …,elementN
-
A JavaScript array is initialized with the given elements, except in the case where a single argument is passed to the
Array
constructor and that argument is a number (see thearrayLength
parameter below). Note that this special case only applies to JavaScript arrays created with theArray
constructor, not array literals created with the square bracket syntax. arrayLength
-
If the only argument passed to the
Array
constructor is an integer between 0 and 232 - 1 (inclusive), this returns a new JavaScript array with itslength
property set to that number (Note: this implies an array ofarrayLength
empty slots, not slots with actualundefined
values — see sparse arrays).
Exceptions
RangeError
-
Thrown if there's only one argument (
arrayLength
) that is a number, but its value is not an integer or not between 0 and 232 - 1 (inclusive).
Examples
Array literal notation
Arrays can be created using the literal notation:
const fruits = ["Apple", "Banana"];
console.log(fruits.length); // 2
console.log(fruits[0]); // "Apple"
Array constructor with a single parameter
Arrays can be created using a constructor with a single number parameter. An array is created with
its length
property set to that number, and the array elements are empty
slots.
const arrayEmpty = new Array(2);
console.log(arrayEmpty.length); // 2
console.log(arrayEmpty[0]); // undefined; actually, it is an empty slot
console.log(0 in arrayEmpty); // false
console.log(1 in arrayEmpty); // false
const arrayOfOne = new Array("2"); // Not the number 2 but the string "2"
console.log(arrayOfOne.length); // 1
console.log(arrayOfOne[0]); // "2"
Array constructor with multiple parameters
If more than one argument is passed to the constructor, a new Array
with
the given elements is created.
const fruits = new Array("Apple", "Banana");
console.log(fruits.length); // 2
console.log(fruits[0]); // "Apple"
Specifications
Specification |
---|
ECMAScript Language Specification # sec-array-constructor |
Browser compatibility
BCD tables only load in the browser
See also
- Indexed collections guide
Array