How to get a key in a JavaScript object by its value ?

Method 1: Checking all the object properties to find the value: The values of the object can be found by iterating through its properties. Each of these properties con be checked to see if they match the value provided. The properties of the object are obtained by using a for loop on the object. These properties are then checked with the object’s hasOwnProperty() method to make sure it is a direct property of the object and not an inherited one.
Each property is then checked if they are equal to the value to be found. If the value matches, then the property is returned. This is the key to the value of the object.

Example:

filter_none

edit
close

play_arrow

link
brightness_4
code

<!DOCTYPE html>
<html>
  
<head>
    <title>
        How to get a key in a JavaScript
        object by its value ?
    </title>
</head>
  
<body>
    <h1 style="color: green">GeeksforGeeks</h1>
      
    <b>
        How to get a key in a JavaScript
        object by its value ?
    </b>
      
    <p>Getting the key of the value '100'.</p>
      
    <p>See the console for the output</p>
  
    <script>
        function getKeyByValue(object, value) {
            for (var prop in object) {
                if (object.hasOwnProperty(prop)) {
                    if (object[prop] === value)
                    return prop;
                }
            }
        }
      
        var exampleObject = {
            key1: 'Geeks',
            key2: 100,
            key3: 'Javascript'
        };
  
        ans = getKeyByValue(exampleObject, 100);
          
        console.log(ans);
    </script>
</body>
  
</html>

chevron_right






                        filter_none








Output:

by-properties-out

Console Output:

by-properties-console


        
          
          
          
        

            

Method 2: Using the find method() to compare the keys: The Object.keys() method is used to return all the keys of the object. On this array of keys, the find() method is used to test if any of these keys match the value provided. The find() method is used to return the value of the first element that satisfies the testing function. If the value matches, then this condition is satisfied and the respective key is returned. This is the key to the value of the object.


Note: This method was added in the ES6 specification and may not be supported on older browser versions.


Syntax:













                                    filter_none




                                    edit

                                    close




                                    play_arrow




                                    link

                                    brightness_4

                                    code
                                




















function getKeyByValue(object, value) { 


    return Object.keys(object).find(key => object[key] === value); 


} 



















                        chevron_right







                        filter_none










Example:











                                    filter_none




                                    edit

                                    close




                                    play_arrow




                                    link

                                    brightness_4

                                    code
                                




















<!DOCTYPE html> 


<html> 


      


<head> 


    <title> 


        How to get a key in a JavaScript 


        object by its value ? 


    </title> 


</head> 


  


<body> 


    <h1 style="color: green">GeeksforGeeks</h1> 


      


    <b>How to get a key in a JavaScript object by its value?</b> 


      


    <p>Getting the key of the value 'Geeks'.</p> 


      


    <p>See the console for the output</p> 


  


    <script> 


        function getKeyByValue(object, value) { 


            return Object.keys(object).find(key =>  


                    object[key] === value); 


        } 


      


        var exampleObject = { 


            key1: 'Geeks', 


            key2: 100, 


            key3: 'Javascript' 


        }; 


      


        ans = getKeyByValue(exampleObject, 'Geeks'); 


        console.log(ans); 


    </script> 


</body> 


  


</html> 



















                        chevron_right







                        filter_none








Output:

by-find-out

Console Output:

by-find-console



          
          
          
          

            

    

        My Personal Notes
        arrow_drop_up
    

    

        
        

            
            
        

    


Recommended Posts:
Image
sayantanm19
Technical Writer Lets have an update
If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please Improve this article if you find anything incorrect by clicking on  the "Improve Article" button below.