Array of functions in JavaScript

Given an array containing functions and the task is to access its element in different ways using JavaScript.

Approach:

  • Declare an array of functions.
  • The array of function works with indexes like an array function.

Example 1: In this example, the function call is initiated from the element of array but the function is defined somewhere else. We can pass arguments to the function while calling.



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<!DOCTYPE HTML> 
<html> 
    <head> 
        <title> 
            Array of functions in javascript
        </title>
    </head> 
      
    <body style = "text-align:center;"> 
          
        <h1 style = "color:green;" > 
            GeeksForGeeks 
        </h1>
          
        <p id = "GFG_UP" style =
            "font-size: 19px; font-weight: bold;">
        </p>
          
        <button onClick = "GFG_Fun()">
            click here
        </button>
          
        <p id = "GFG_DOWN" style = 
            "color: green; font-size: 24px; font-weight: bold;">
        </p>
          
        <script>
            var up = document.getElementById('GFG_UP');
            var down = document.getElementById('GFG_DOWN');
              
            function firstFun(str) {
                down.innerHTML = str;
            }
            function secondFun(str) {
                down.innerHTML = str;
            }
            function thirdFun(str) {
                down.innerHTML = str;
            }
              
            // Declare array of functions
            var arrayOfFunction = [
                firstFun,
                secondFun,
                thirdFun     
            ]
              
            up.innerHTML = "Calling function from the array of functions";
              
            // Function call
            function GFG_Fun() {
                arrayOfFunction[0]("This is first function");
            }
        </script> 
    </body> 
</html>                    

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Output:


    

  • 
Before clicking on the button:
    


    • 

  • 
After clicking on the button:
    


    • 



Example 2: In this example, the function (anonymous) itself is defined as the elements of array. We can access it by accessing the element of array followed by ().











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<!DOCTYPE HTML>  


<html>  


    <head>  


        <title>  


            Array of functions in JavaScript 


        </title> 


    </head>  


      


    <body style = "text-align:center;">  


          


        <h1 style = "color:green;" >  


            GeeksForGeeks  


        </h1> 


          


        <p id = "GFG_UP" style =  


            "font-size: 19px; font-weight: bold;"> 


        </p> 


          


        <button onClick = "GFG_Fun()"> 


            click here 


        </button> 


          


        <p id = "GFG_DOWN" style = 


            "color: green; font-size: 24px; font-weight: bold;"> 


        </p> 


          


        <script> 


            var up = document.getElementById('GFG_UP'); 


            var down = document.getElementById('GFG_DOWN'); 


              


            // Declare an array of functions 


            var arrayOfFunction = [ 


                function() { 


                    down.innerHTML = "Inside First function"; 


                }, 


                  


                function() { 


                    down.innerHTML = "Inside Second function"; 


                }, 


                  


                function() { 


                    down.innerHTML = "Inside Third function"; 


                }      


            ] 


              


            up.innerHTML = "Calling function from the array of functions"; 


              


            function GFG_Fun() { 


                arrayOfFunction[2](); 


            } 


        </script>  


    </body>  


</html>                     



















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Output:


    

  • 
Before clicking on the button:
    


    • 

  • 
After clicking on the button:
    


    • 




          
          
          
          

            

    

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