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JavaScript splice function

With JavaScript splice() function, we can change an array.  With this function, you can add or remove a value from the array given with a specific index location in the array.

The syntax structure is 

arr.splice(index, count, [items...]);

  1. index--> from where to start to remove or add
  2. count-->whether to add or remove
  3. items--> what to add or remove. This is optional 

If index 2, and count 0, then nothing would be removed from the below array but will add "orange" to the array.

<!DOCTYPE html>
<html>
<head>
    <title>
        JavaScript splice() Method
    </title>
</head>
  
<body>
  
    <script>
        let arr=["apple", "banana", "milk"];
        arr.splice(2, 0, "orange");
        console.log(arr);
    </script>
</body>
  
</html>

And the output would be below

["apple", "banana", "orange", "milk"]

So count = 0 means don't remove. It means add something at the third place which index is 2.

See the below example with index 3 and count 1

<!DOCTYPE html>
<html>
<head>
    <title>
        JavaScript splice() Method remove item
    </title>
</head>
  
<body>  
    <script>
        let arr = ["apple", "banana", "milk", "juice"];
        newArr = arr.splice(3, 1);
        console.log(arr);
    </script>
</body>
  
</html>

Since index is 3 and count is 1, splice function will remove an element from the fourth position ( index is 3) of the array. and the new array would be

["apple", "banana", "milk"]

So if the count parameter mentioned in splice() method is non-zero, it will remove an item or items. It's totally based number of parameters. Non-zero means remove

See more examples

<html>
   <head>
      <title>JavaScript splice Method Example</title>
   </head>
   
   <body>   
      <script type = "text/javascript">
         var arr = ["orange", "mango", "banana", "sugar", "tea"];         
         var removed = arr.splice(2, 0, "water");
         console.log("After adding 1: " + arr );
        console.log("<br />removed is: " + removed);
         
         removed = arr.splice(3, 1);
         console.log("<br />After adding 1: " + arr );
         console.log("<br />removed is: " + removed);
      </script>      
   </body>
</html>