splice method
The splice method removes or adds
elements to an array. You can only remove
items, only add items, or do both at the
same time. The method is very versatile
and difficult to understand. The method
changes the array itself and returns an
array of removed elements.
The first parameter of the method is
the number of the array element to be
removed. The second parameter is how many
elements of the array should be removed. If
it is set to 0, then the elements
will not be removed (only new ones will
be added). Then, separated by commas,
there are elements that need to be added
to the array (these parameters are
optional). These elements will be added
instead of the removed ones.
If there was no deletion (when the second
parameter is 0), the elements will
be inserted into the array starting from
the position specified by the first
parameter of the method. The first parameter
can be negative. In this case, the position
count will start not from the beginning
of the array, but from the end. The last
element in this case will have the number
-1.
Syntax
array.splice(from where to remove, how much to remove, [insert], [insert]...);
Example
Let's remove three elements starting from the first:
let arr = ['a', 'b', 'c', 'd', 'e'];
arr.splice(1, 3);
console.log(arr);
The code execution result:
['a', 'e']
Example
Let's output the array of removed elements:
let arr = ['a', 'b', 'c', 'd', 'e'];
let del = arr.splice(1, 3);
console.log(del);
The code execution result:
['b', 'c', 'd']
Example
Let's first remove the element with
the number 2, and then insert
three more new elements instead:
let arr = ['a', 'b', 'c', 'd', 'e'];
arr.splice(2, 1, '1', '2', '3');
console.log(arr);
The code execution result:
['a', 'b', '1', '2', '3', 'd', 'e']
Example
Let's not delete anything now, but at
the position 2, insert three
more new elements:
let arr = ['a', 'b', 'c', 'd', 'e'];
arr.splice(2, 0, '1', '2', '3');
console.log(arr);
The code execution result:
['a', 'b', '1', '2', '3', 'c', 'd', 'e']
Example . Negative value
Let's remove the second to last element:
let arr = ['a', 'b', 'c', 'd', 'e'];
arr.splice(-2, 1);
console.log(arr);
The code execution result:
['a', 'b', 'c', 'e']
