The keys() function of Map object is similar to entries but, it returns an iterator object containing the keys of a map object.
Syntax
Its Syntax is as follows
Map.keys()
Example
<html>
<head>
<title>JavaScript Example</title>
</head>
<body>
<script type="text/javascript">
var mapVar = new Map();
mapVar.set('1', 'Java');
mapVar.set('2', 'JavaFX');
mapVar.set('3', 'HBase');
mapVar.set('4', 'Neo4j');
var it = mapVar.keys();
for(i=0; i<mapVar.size; i++) {
document.write(it.next().value);
document.write(" <p> ");
}
</script>
</body>
</html>Output
1 2 3 4