While developing a website using JavaScript, there are some situations when the programmers need to delete/remove some elements from an array. To do so, JavaScript allows some pre-built methods or properties, such as the “delete” or the “splice()” method. The delete operator deletes the element from an array but does not rearrange the array, while the splice() method rearranges the array.

This blog will describe the difference between the JavaScript delete and splice() method.

JavaScript delete vs splice

The “delete” or the “splice()” are the two ways in JavaScript utilized to delete the elements from an array, but they each have their benefits in terms of how they achieve the deletion. For instance, the JavaScript “delete” operator deletes the element and replaces it with the keyword “empty”. It does not change the array’s length even after deleting an element. While the “splice()” method deletes the value with its associated index to maintain the sequence.

Let’s discuss these approaches individually with examples.

How to Use “delete” Operator in JavaScript?

In JavaScript, the “delete” operator deletes the element from the specified index but does not change the array. This signifies that the element is left undefined or null in place of the deleted index. Such a scenario causes an issue while iterating across the array because the deleted index has no value. Moreover, the array’s length remains constant.

Syntax

Use the following syntax to use the delete operator for deleting an element from an array:

Example

First, create an array of positive and negative numbers:

Here, we will delete the number “-8” from the first index of an array that is “0” using the delete operator:

The output display “true” which means the specified element from an array is deleted:

Print the array after deleting the element:

As you can see, the array contains “empty” at the 0 index which shows that the element from this index is deleted, but the array is not modified:

If you want to access the value at the deleted index, it will output “undefined” because the element has been deleted:

Output

How to Use “splice()” in JavaScript?

For adding and removing elements from an array, use the “splice()” method. This method deletes/removes elements at the index and shifts/move the other elements, so there is no empty index. This is beneficial since the remaining array after deletion can be iterated and presented normally. Using this strategy, the length of the array can be reduced.

Syntax

The following syntax is utilized for deleting elements from an array utilizing the “splice()” method:

Here:

• “index” is the specified index where the element will be deleted.
• “deleteCount” refers to the number of elements in an array that need to be deleted.

It is also used to add some elements as a replacement for the deleted elements. For this purpose, use the given syntax:

The above syntax represents three parameters:

• “index” at which the deleted element is placed.
• “deleteCount” indicates the number of elements to be deleted/eliminated.
• “item” is the new item that needs to be placed.

Example

Call the splice() method and pass the index of the element “12” from an array that is “3” and the “deleteCount” is “1”, which means delete one element from an array:

It can be seen that the “12” has been successfully deleted from an array, and the elements are rearranged in the array:

You can also use the splice() method to insert new elements into an array by providing additional arguments after the number of elements to remove. Here, we will add “11” in place of “12”:

That was all about the usage of the delete operator and splice() method in JavaScript.

Conclusion

In JavaScript, the “delete” operator removes a property or element from an array or object. It does not modify the object’s length or affect the indices of any other properties. On the other hand, the “splice()” method is utilized to rearrange the elements of an array by removing/replacing them. It modifies the array’s length and affects the indices of subsequent elements. The splice() method is the best option for deleting elements from an array. This blog described the difference between the JavaScript delete and splice() method.