Java Script – For/OF Loop

For/Of Loop:

  • It is called enhanced for loop
  • It is used to iterate Array or Collection easily.

Note: Generally, we iterate an array by specifying their index values.

<html>
	<body>
		<script>
			var arr = [10, 20, 30, 40, 50];
			document.write("Array elements are : <br/>");
			for (var i=0 ; i<arr.length ; i++){
				document.write(arr[i] + "<br/>");
			}
		</script>
	</body>
</html>

In case of For/Of loop, no need to specify the index to iterate the elements of Array or Collection:

<html>
	<body>
		<script>
			var arr = [10, 20, 30, 40, 50];
			document.write("Array elements are : <br/>");
			for(var x of arr){
				document.write(x + "<br/>");
			}
		</script>
	</body>
</html>

We can iterate any type of array using for/of easily:

<html>
	<body>
		<script>
			var arr=["HTML", "JavaScript", "CSS", "Angular", "VueJS"];
			document.write("Array elements are : <br/>");
			for(var s of arr){
				document.write(s + "<br/>");
			}
		</script>
	</body>
</html>

Limitations: For/of loop can process elements only in forward direction. For/of loop can process elements one by one

Display Array in Reverse Order: We must use for loop only

<html>
	<body>
		<script>
			var arr = [10, 20, 30, 40, 50];
			document.write("Array elements are : <br/>");
			for(var i=arr.length-1 ; i>=0 ; i--){
				document.write(arr[i] + "<br/>");
			}
		</script>
	</body>
</html>

for/of loop: To process elements of Array/Collection only in forward direction.

Display even number in the given array using for-loop:

<html>
	<body>
		<script>
			var arr = [5, 2, 9, 1, 6, 4, 7, 3];
			document.write("Even elements : <br/>");
			for(var i=0 ; i<arr.length ; i++){
				if(arr[i]%2==0)
					document.write(arr[i] + "<br/>");
			}
		</script>
	</body>
</html>

The above program we can easily perform using for/of loop:

<html>
	<body>
		<script>
			var arr = [5, 2, 9, 1, 6, 4, 7, 3];
			document.write("Even elements : <br/>");
			for(var x of arr){
				if(x%2==0)1
					document.write(x + "<br/>");
			}
		</script>
	</body>
</html>
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