JavaScript | array.keys()

The array.keys() is an inbuilt function in JavaScript which is used to return a new array iterator which contains the keys for each index in the given input array.

Syntax:

array.keys()

Parameter: It doesn’t take any parameter.

Return Values: It returns a new array iterator.

JavaScript code to show working of array.keys() function:

Code #1:

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<script>
  
   // Taking input as an array A 
   // containing some elements.
   var A = [ 'gfg', 'geeks', 'cse', 'geekpro' ];
  
  // array.keys() function is called
   var iterator = A.keys();
  
  // printing index array using the iterator
   for (let key of iterator) {
    document.write(key + ' ');
   }
</script>

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Output:


0 1 2 3 


Code #2:











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<script> 


  


  // Taking input as an array A 


  // containing some elements 


  var A = [ 'gfg', 'geeks', 'cse', 'geekpro', '', 1, 2 ]; 


  


  // array.keys() function is called 


  var iterator = A.keys(); 


  


  // printing index array using the iterator 


  for (let key of iterator) { 


    document.write(key + ' '); 


  } 


</script> 



















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Output:


0 1 2 3 4 5 6 



          
          
          
          

            

    

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