How to check whether an array is subset of another array using JavaScript ?

The task is to check whether an array is a subset of another array with the help of JavaScript. Here are a few techniques discussed.
Approach 1:

This approach checks whether every element of the second array is present in the first array or not.

Example 1: This example uses the approach as discussed above.

<!DOCTYPE HTML> 
<html> 
  
<head> 
    <title> 
        check whether an array is  
      subset of another array using JavaScript 
    </title> 
</head> 
  
<body style="text-align:center;"> 
    <h1 style="color:green;">   
            GeeksForGeeks   
        </h1> 
    <p id="GFG_UP" 
       style="font-size: 15px; 
              font-weight: bold;"> 
    </p> 
    <button onclick="GFG_Fun()"> 
        click here 
    </button> 
    <p id="GFG_DOWN" 
       style="color:green; 
              font-size: 20px; 
              font-weight: bold;"> 
    </p> 
    <script> 
        var up = document.getElementById('GFG_UP'); 
        var down = document.getElementById('GFG_DOWN'); 
        var arr1 = ["GFG", "Geeks", "Portal", "Geek", "GFG_1", "GFG_2"]; 
        var arr2 = ["GFG", "Geeks", "Geek"]; 
        up.innerHTML =  
          "Click on the button to check the subset property."+ 
          "<br>Array1-" + arr1 + "<br>Array2-" + arr2; 
  
        function GFG_Fun() { 
            res = arr2.every(function(val) { 
                return arr1.indexOf(val) >= 0; 
            }); 
            not = ""; 
            if (!res) { 
                not = "not"; 
            } 
            down.innerHTML =  
              "Array_2 is " + not + " the subset of Array_1"; 
        } 
    </script> 
</body> 
  
</html> 

Output:

Before clicking on the button:
After clicking on the button:

Approach 2:

This approach declares false if some element of second array is not present in first array.

Example 2: This example uses the approach as discussed above.

<!DOCTYPE HTML> 
<html> 
  
<head> 
    <title> 
        check whether an array is subset  
      of another array using JavaScript 
    </title> 
</head> 
  
<body style="text-align:center;"> 
    <h1 style="color:green;">   
            GeeksForGeeks   
        </h1> 
    <p id="GFG_UP" 
       style="font-size: 15px; 
              font-weight: bold;"> 
    </p> 
    <button onclick="GFG_Fun()"> 
        click here 
    </button> 
    <p id="GFG_DOWN" 
       style="color:green; 
              font-size: 20px;  
              font-weight: bold;"> 
    </p> 
    <script> 
        var up = document.getElementById('GFG_UP'); 
        var down = document.getElementById('GFG_DOWN'); 
        var arr1 = ["GFG", "Geeks", "Portal", "Geek", "GFG_1", "GFG_2"]; 
        var arr2 = ["GFG", "Geeks", "GeekForGeeks"]; 
        up.innerHTML = "Click on the button to check the subset property."+ 
          "<br>Array1-" + arr1 + "<br>Array2-" + arr2; 
  
        function GFG_Fun() { 
            res = !arr2.some(val => arr1.indexOf(val) === -1); 
            not = ""; 
            if (!res) { 
                not = "not"; 
            } 
            down.innerHTML = "Array_2 is "  
            + not + " the subset of Array_1"; 
        } 
    </script> 
</body> 
  
</html> 

Output:

Before clicking on the button:
After clicking on the button:

My Personal Notes

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