Saturday, September 6, 2025
HomeLanguagesJavascriptHow to flatten array with the JavaScript/jQuery ?

How to flatten array with the JavaScript/jQuery ?

JavaScript contains many arrays (or 2-d array) and the task is to flatten the array and make that look like 1-d JavaScript array. There are two approaches that are discussed below. You can also use Underscore.js _.flatten() with Examples.

Approach 1: Use Array.prototype.concat.apply() method to perform the operation. The concat() and apply() method is used to concat the arrays to 1-d array.

  • Example:




    <!DOCTYPE HTML>
    <html>
      
    <head>
        <title>
            How to flatten array with
            the JavaScript?
        </title>
          
        <style>
            body {
                text-align: center;
            }
              
            h1 {
                color: green;
            }
        </style>
    </head>
      
    <body>
        <h1>neveropen</h1>
          
        <p id="GFG_UP"></p>
          
        <button onClick="GFG_Fun()">
            click here
        </button>
          
        <p id="GFG_DOWN"></p>
          
        <script>
            var up = document.getElementById('GFG_UP');
            var down = document.getElementById('GFG_DOWN');
            var arr1 = [1, 2, 3];
            var arr2 = [4, 5, 6, 7];
            var arr = [arr1, arr2, 8, 9];
              
            up.innerHTML = "Click on button to get "
                    + "the common elements from these"
                    + " array <br>Array -[[" + arr[0]
                    + "], [" + arr[1] + "], " + arr[2]
                    + ", " + arr[3] + "]";
      
            function GFG_Fun() {
                down.innerHTML = 
                    Array.prototype.concat.apply([], arr);
            }
        </script>
    </body>
      
    </html>

    
    
  • Output:

Approach 2: The $.map() method in jQuery can be used to perform the operation. This method takes the array and a method as input. The second argument which is a method takes elements of original array one by one and return its elements.

  • Example:




    <!DOCTYPE HTML>
    <html>
      
    <head>
        <title>
            How to flatten array with
            the JavaScript?
        </title>
          
        <style>
            body {
                text-align: center;
            }
              
            h1 {
                color: green;
            }
        </style>
        <script src=
        </script>
    </head>
      
    <body>
        <h1>neveropen</h1>
          
        <p id="GFG_UP"></p>
          
        <button onClick="GFG_Fun()">
            click here
        </button>
          
        <p id="GFG_DOWN"></p>
          
        <script>
            var up = document.getElementById('GFG_UP');
            var down = document.getElementById('GFG_DOWN');
            var arr1 = [1, 2, 3];
            var arr2 = [4, 5, 6, 7];
            var arr = [arr1, arr2, 8, 9];
              
            up.innerHTML = "Click on button to get the"
                    + " common elements from these array"
                    + "<br>Array - [[" + arr[0] + "], ["
                    + arr[1] + "], " + arr[2] + ", " 
                    + arr[3] + "]";
      
            function GFG_Fun() {
                down.innerHTML = $.map(arr, function(n) {
                    return n;
                });
            }
        </script>
    </body>
      
    </html>

    
    
  • Output:
Whether you’re preparing for your first job interview or aiming to upskill in this ever-evolving tech landscape, neveropen Courses are your key to success. We provide top-quality content at affordable prices, all geared towards accelerating your growth in a time-bound manner. Join the millions we’ve already empowered, and we’re here to do the same for you. Don’t miss out – check it out now!
RELATED ARTICLES

Most Popular

Dominic
32269 POSTS0 COMMENTS
Milvus
81 POSTS0 COMMENTS
Nango Kala
6639 POSTS0 COMMENTS
Nicole Veronica
11803 POSTS0 COMMENTS
Nokonwaba Nkukhwana
11868 POSTS0 COMMENTS
Shaida Kate Naidoo
6752 POSTS0 COMMENTS
Ted Musemwa
7029 POSTS0 COMMENTS
Thapelo Manthata
6704 POSTS0 COMMENTS
Umr Jansen
6721 POSTS0 COMMENTS