What is the Efficient way to insert a number into a sorted array of numbers in JavaScript ?

Last Updated : 12 Jul, 2025

Given an array of numbers and the task is to insert a number into the sorted array using JavaScript. There are many approaches to solving this problem two of which are given below:

Approach 1:

First, take the values in a variable (lets arr).
Make sure it is sorted.
In this example, the complexity is O(n), where n is the number of elements in the array available.
The method findLoc is searching for the element just greater than the element that we want to insert.
The method returns the index of the location.
perform the insert operation using the .splice() method.

Example: This example illustrates the approach discussed above.

html

<h1 style="color:green;">
    GeeksforGeeks
</h1>
<p id="GFG_UP">
</p>
<button onclick="gfg_Run()">
    Insert
</button>
<p id="GFG_DOWN">
</p>
<script>
    var el_up = document.getElementById("GFG_UP");
    var el_down = document.getElementById("GFG_DOWN");
    var today = new Date();
    var arr = [1, 2, 4, 6, 9];
    el_up.innerHTML = "Click on the button to insert a number "+
                "in javascript array.<br> Array is = " + arr;
    
    function add(el, arr) {
        arr.splice(findLoc(el, arr) + 1, 0, el);
        return arr;
    }
    
    function findLoc(el, arr, st, en) {
        st = st || 0;
        en = en || arr.length;
        for (i = 0; i < arr.length; i++) {
            if (arr[i] > el)
                return i - 1;
        }
        return en;
    }
    
    function gfg_Run() {
        add(7, arr);
        el_down.innerHTML = "Array becomes " + arr;
    }
</script>

Output:

What is the Efficient way to insert a number into a sorted array of numbers in JavaScript?

Approach 2:

In this example, the complexity is O(Logn), where n is the number of elements in the array.
A method findLoc is searching for the location where the element should be present.
Method returns the index of the location by using binary search algorithm.
perform the insert operation using .splice() method.

Example: This example illustrate the approach discussed above.

html

<h1 style="color:green;">
    GeeksforGeeks
</h1>
<p id="GFG_UP"></p>
<button onclick="gfg_Run()">
    Insert
</button>
<p id="GFG_DOWN"></p>
<script>
    var el_up = document.getElementById("GFG_UP");
    var el_down = document.getElementById("GFG_DOWN");
    var today = new Date();
    var arr = [1, 2, 4, 6, 9];
    el_up.innerHTML = "Click on the button to insert a "+
    "number in javascript array.<br> Array is = " + arr;
    
    function add(el, arr) {
        arr.splice(findLoc(el, arr) + 1, 0, el);
        return arr;
    }
    
    function findLoc(el, arr, st, en) {
        st = st || 0;
        en = en || arr.length;
        var pivot = parseInt(st + (en - st) / 2, 10);
        if (en - st <= 1 || arr[pivot] === el) return pivot;
        if (arr[pivot] < el) {
            return findLoc(el, arr, pivot, en);
        } else {
            return findLoc(el, arr, st, pivot);
        }
    }
    
    function gfg_Run() {
        add(5, arr);
        el_down.innerHTML = "Array becomes " + arr;
    }
</script>