Remove element from array, using slice

I am trying to remove a element from my array using slice, but i can’t get it to work, look at this piece of code.

    console.log(this.activeEffects); // Prints my array
    console.log(this.activeEffects.slice(0,1)); // Remove from index 0, and remove one.
    console.log(this.activeEffects); // Prints array again, this time my element should be gone

Result of this is.

enter image description here

So what is get from this is, at first the array is whole, as it should be. Then its prints what is sliced of the array. Finally the third should be empty? or?

function removeItemWithSlice(index) {
  return [...items.slice(0, index), ...items.slice(index + 1)]

Slice will create a new array. We create two arrays: from beggining to index and from index+1 to end. Then we apply the spread operator (…) to take the items of those arrays and create a new single array containing all the items we care. I will paste an equivalent way if you don’t like the one liner:

function removeItemWithSlice(index) {
  const firstArr = items.slice(0, index);
  const secondArr = items.slice(index + 1);
  return [...firstArr , ...secondArr]

I believe you’re looking for splice. From W3 Schools:

The splice() method adds/removes items to/from an array, and returns the removed item(s).

Take a look at the example on that page; the use case there is similar to what you want to achieve.

EDIT: Alternative link to MDN, as suggested by Nicosunshine; much more information about the command there.

a.slice(0, index).concat(a.slice(index + 1))

.slice does not mutate the array, you could use .splice() to remove the item at index i in the array:

this.activeEffects.splice(i, 1)

This is what I was able to come up with :

var newArray = oldArray.slice(indexOfElementToRemove+1).concat(oldArray.slice(0,indexOfElementToRemove));


does not alter the original array, but returns a new “one level
deep” copy that contains copies of the elements sliced from the
original array. Elements of the original array are copied into the new
array as follows:

Whereas Array.prototype.splice()

Changes the content of an array, adding new elements while removing old elements.

This example should illustrate the difference.

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// sample array
var list = ["a","b","c","d"];
// slice returns a new array
console.log("copied items: %o", list.slice(2));
// but leaves list itself unchanged
console.log("list: %o", list);
// splice modifies the array and returns a list of the removed items
console.log("removed items: %o", list.splice(2));
// list has changed
console.log("list: %o", list);

Look at here :

You can see that the slice method select object et throw them into a new array object ^^ So you can’t delete an object like this, may be you can try a thing like this :

var a = ["a","b","c"]; (pseudo code)
/* I wan't to remove the "b" object */

var result = a.slice(0,1)+a.slice(2,1); /* If you considers that "+" is a concatenation operator, i don't remember if it is true... */

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