Array() constructor

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 the arrayLength parameter below). Note that this special case only applies to JavaScript arrays created with the Array constructor, not array literals created with the 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 its length property set to that number (Note: this implies an array of arrayLength empty slots, not slots with actual undefined values — see sparse arrays).

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).

Arrays can be created using the literal notation:

const fruits = ["Apple", "Banana"];

console.log(fruits.length); // 2
console.log(fruits[0]); // "Apple"

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"

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"

• Indexed collections guide
• Array