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...]);
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>