Javascript splice last element

Question

var arr = [1, 2, 3, 4, 5]
console.log(arr)
//[1, 2, 3, 4, 5]
arr = arr.splice(4, 1)
console.log(arr)
//[5]

I want to remove only the last element. Why does it remove every element except the last one?

Answer 1

You need to omit the assignment.

 var arr = [1, 2, 3, 4, 5] console.log(...arr); // [1, 2, 3, 4, 5] arr.splice(4, 1); console.log(...arr); // [1, 2, 3, 4]

If you like just to delete the last one, you could take a negative index with Array#splice . This works for any other index from the end.

 var arr = [1, 2, 3, 4, 5] console.log(...arr); // [1, 2, 3, 4, 5] arr.splice(-1, 1); console.log(...arr); // [1, 2, 3, 4]

Answer 2

Array#splice modifies the array in place and returns the removed portion. You should not reassign the removed portion to the variable.

 var arr = [1, 2, 3, 4, 5] arr.splice(4, 1) console.log(arr);

Answer 3

splice alters the array and returns the removed item(s) in a new array.

By the way, you should use pop which is better suited for this like so:

 var arr = [1, 2, 3, 4, 5]; arr.pop(); console.log(arr);

pop removes the last item of the array.

Answer 4

The splice method takes two parameters: a beginning index (inclusive) and an ending index (exclusive). The below will do what you described.

arr = arr.splice(0, 4)

Answer 5

This is a more general approach:

 var arr = [1, 2, 3, 4, 5] arr.splice(arr.length - 1); console.log(arr)

Answer 6

You can access to the last arr element by splice(-1), then you stored that value (5) into a variable (newArr). The original array now values [1, 2, 3, 4].

 let arr = [1, 2, 3, 4, 5]; let newArr = arr.splice(-1); console.log(arr) //[1, 2, 3, 4] console.log(newArr) //[5]

Answer 7

In your code, you are reassigning the arr to the spliced value, which is [5]. the way you should do it is,

 var arr = [1, 2, 3, 4, 5]
     console.log(arr)
   //[1, 2, 3, 4, 5]
     arr.splice(4, 1)
     console.log(arr)
   //[1, 2, 3, 4]

This should give you the result you are looking for;

Answer 8

The splice() method adds/removes items to/from an array, and returns the removed items in the form of an array.

Syntax: let arrDeletedItems = array.splice(starting_index, index to which you want to add or remove an item, item 1, item 2, item 3...so on )

let arr = [1, 2, 3, 4, 5] arr.splice(4, 1)

so in your case, you are starting from index 4 which means the value "5" and you are removing the 1st element that starts from index 4 which is the value '5'. So the splice method would return a new array (as it returns a new array of the removed elements) containing only 5.

To get back an array containing all the elements except the last element 5 you should write: arr = arr.splice(0,4) which means that start from index 0 and remove elements till index 4.

Answer 9

You can also remove the last element from the array with rest operator

const array = [1, 2, 3, 4, 5]
const [ ...newArray, last ] = array

Answer 10

Splice method returns the removed item(s) in an array so what is happening is you are assigning the returned to the original array. Instead do this

var arr = [1, 2, 3, 4, 5];
console.log(arr);
//[1, 2, 3, 4, 5]
arr.splice(4, 1);
console.log(arr);

Answer 11

Splice modifies array in place and returns removed part as a new array. To get expected result you want to use expression:

var arr = [1, 2, 3, 4, 5]
console.log(arr)
//[1, 2, 3, 4, 5]
arr.splice(4, 1)
console.log(arr)
//[5]