JavaScript Removing items from an array


Example

Shift

Use .shift to remove the first item of an array.

For example:

var array = [1, 2, 3, 4];
array.shift();

array results in:

[2, 3, 4]

Pop

Further .pop is used to remove the last item from an array.

For example:

var array = [1, 2, 3];
array.pop();

array results in:

[1, 2]

Both methods return the removed item;

Splice

Use .splice() to remove a series of elements from an array. .splice() accepts two parameters, the starting index, and an optional number of elements to delete. If the second parameter is left out .splice() will remove all elements from the starting index through the end of the array.

For example:

var array = [1, 2, 3, 4];
array.splice(1, 2);

leaves array containing:

[1, 4]

The return of array.splice() is a new array containing the removed elements. For the example above, the return would be:

[2, 3]

Thus, omitting the second parameter effectively splits the array into two arrays, with the original ending before the index specified:

var array = [1, 2, 3, 4];
array.splice(2);

...leaves array containing [1, 2] and returns [3, 4].

Delete

Use delete to remove item from array without changing the length of array:

var array = [1, 2, 3, 4, 5];
console.log(array.length); // 5
delete array[2];
console.log(array); // [1, 2, undefined, 4, 5]
console.log(array.length); // 5

Array.prototype.length

Assigning value to length of array changes the length to given value. If new value is less than array length items will be removed from the end of value.

array = [1, 2, 3, 4, 5];
array.length = 2;
console.log(array); // [1, 2]