JavaScript Array entries() Method

The entries() method creates a new iterator object of an array, holding the key/value pairs for every value in the array. A key represents the index number carrying an item as its value. It does not affect the original array.

Syntax

The following syntax represents the entries() method:

Parameters

It does not have any parameters.

Return

It returns the newly created array iterator object. The iterator object represents each element of the array with keys assigned to them.

JavaScript Array entries() Method Examples

Let's implement some examples to understand the toString() method better:

Example1: A simple array entries() method an array.

<html>
<head> <h5> Array Methods </h5>
<body>
	<script>
	var arr=['John','Michael','Embrose','Herry','Lewis'];
	var itr=arr.entries();
	document.write("After applying the entries method:"+"<br>");

	for(var e of itr) //for loop using var.
	{
		document.write(e+"</br>");
	}
	</script>
</body>
</head>
</html>

Test it Now

Output:

The output shows the elements of the array with key assigned to it. Thus, together forms a key/value pair.

Example2: This example represents the array entries() method through let declaration.

<html>
<head> <h5> Array Methods </h5>
<body>
	<script>
	var arr=['John','Michael','Embrose','Herry','Lewis']; // array elements
	var itr=arr.entries();
	document.write("After applying the entries method:"+"<br>");

	for(let e of itr) // let declares a variable, but its scope is within the block.
	{
		document.write(e+"</br>");
	}
	</script>
</body>
</head>
</html>

Test it Now

Output:

The output will be same as shown in the above example.

Example3: This example displays the (key,value) pairs of the array by clicking on the "apply" button.

<html>
<head> <h5> Array Methods </h5>
<body>
	<script>
		function arr()
		{
		       var name=['John','Serious','Hadrik','Harry'];
		        var itr=name.entries(); //Using entries() method.
	                     document.write("After applying the entries method:"+"<br>");
		         for(x of itr)
			{
			document.write("<br>"+x); //This will display one array                 element per line. 
			}
		}
		</script>
</body>
<input type="button" onClick="arr()" value=" Apply"/> //invoking the arr() function.
</head>
</html>

Test it Now

Output:

After calling the arr() function, the output comes out:

Example4: Displaying the position of the candidates in the given array.

<html>
<head> <h5> Array Methods </h5>
<body>
	<script>
		function position()
		{
			var name=['John','Serious','Hadrik','Harry'];
			var itr=name.entries(); //Using entries() method.
			document.write("The positions of each candidate in a sequence are:  "+"<br>");
			for(x of itr)
			{
				document.write("<br>"+x); //This will display one array element per line with its key. 
			}
		}
		</script>
</body>
<input type="button" onClick="position()" value=" Click to Display"/> 
</head>
</html>

Test it Now

Output:

The output will be:

Example5:

<html>
<head> <h5> Array Methods </h5>
<body>
	<script>
		function position()
		{
			var name=[1,2,3,4,5,6,7,8,8,9];
			var itr=name.entries(); //Using entries() method.
			document.write("The positions of each number in a sequence are:  "+"<br>");
			for(x of itr)
			{
				document.write("<br>"+x); //This will display one array element per line with its key. 
			}
		}
		</script>
</body>
<input type="button" onClick="position()" value=" Click to Display"/> 
</head>
</html>

Test it Now

Output:

After clicking on the "display" button, the position of each number in the array will be: