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JavaScript Map keys() methodThe JavaScript map keys() method returns an object of new Map iterator. This object contains the key for each element. It maintains insertion order. SyntaxThe keys() method is represented by the following syntax: mapObj.keys() ReturnA new object of Map iterator. JavaScript Map keys() method exampleHere, we will understand keys() method through various examples. Example 1Let's see a simple example of keys() method. <script> var map=new Map(); map.set(1,"jQuery"); map.set(2,"AngularJS"); map.set(3,"Bootstrap"); var itr=map.keys(); document.writeln(itr.next().value+"<br>"); document.writeln(itr.next().value+"<br>"); document.writeln(itr.next().value); </script> Output: 1 2 3 Example 2Let's see the same example using for loop. <script> var map=new Map(); map.set(1,"jQuery"); map.set(2,"AngularJS"); map.set(3,"Bootstrap"); var itr=map.keys(); for(i=0;i<map.size;i++) { document.writeln(itr.next().value+"<br>"); } </script> Output: 1 2 3
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