Deleting array elements in JavaScript - delete vs splice

Question

What is the difference between using the delete operator on the array element as opposed to using the Array.splice method?

For example:

myArray = [\         


        

Answer 1

you can use something like this

var my_array = [1,2,3,4,5,6];
delete my_array[4];
console.log(my_array.filter(function(a){return typeof a !== 'undefined';})); // [1,2,3,4,6]

Answer 2

For those who wants to use Lodash can use: myArray = _.without(myArray, itemToRemove)

Or as I use in Angular2

import { without } from 'lodash';
...
myArray = without(myArray, itemToRemove);
...

Answer 3

delete: delete will delete the object property, but will not reindex the array or update its length. This makes it appears as if it is undefined:

splice: actually removes the element, reindexes the array, and changes its length.

Delete element from last

arrName.pop();

Delete element from first

arrName.shift();

Delete from middle

arrName.splice(starting index,number of element you wnt to delete);

Ex: arrName.splice(1,1);

Delete one element from last

arrName.splice(-1);

Delete by using array index number

 delete arrName[1];

Answer 4

If the desired element to delete is in the middle (say we want to delete 'c', which its index is 1), you can use:

var arr = ['a','b','c'];
var indexToDelete = 1;
var newArray = arr.slice(0,indexToDelete).combine(arr.slice(indexToDelete+1, arr.length))

Answer 5

Currently there are two ways to do this

1. using splice()

   arrayObject.splice(index, 1);

2. using delete

   delete arrayObject[index];

But I always suggest to use splice for array objects and delete for object attributes because delete does not update array length.

Answer 6

Array.remove() Method

John Resig, creator of jQuery created a very handy Array.remove method that I always use it in my projects.

// Array Remove - By John Resig (MIT Licensed)
Array.prototype.remove = function(from, to) {
  var rest = this.slice((to || from) + 1 || this.length);
  this.length = from < 0 ? this.length + from : from;
  return this.push.apply(this, rest);
};

and here's some examples of how it could be used:

// Remove the second item from the array
array.remove(1);
// Remove the second-to-last item from the array
array.remove(-2);
// Remove the second and third items from the array
array.remove(1,2);
// Remove the last and second-to-last items from the array
array.remove(-2,-1);

John's website