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JavaScript - TypedArray entries() Method

The JavaScript TypedArray entries() method returns an array iterator object that contains key and value pairs for each index in the typed array. This particular method is not applicable to all arrays and can only be invoked on instances of typed arrays.

The entries() and values() methods of TypedArray object are similar. Both return an iterator object of the type array, only difference between them is that the object returned by the values() method contains single elements at each index. Whereas, the iterator object returned by the entries() method contains key-value pairs.

Syntax

Following is the syntax of JavaScript TypedArray entries() method −

entries()

Parameters

  • It does not accept any parameters.

Return value

This method returns a new array iterable object.

Examples

Example 1

The following program demonstrates the usage of the JavaScript TypedArray entries() method.

<html>
<head>
   <title>JavaScript TypedArray entries() Method</title>
</head>
<body>
   <script>
      const T_array = new Uint8Array([1, 2, 3, 4, 5]);
      document.write("The original typed array: ", T_array);
      
      //using the entries() method
      let new_array = T_array.entries();
      document.write("<br>The new_array iterator object: ", new_array);
   </script>    
</body>
</html>

Output

The above program returns a new "object Array iterator".

The original typed array: 1,2,3,4,5
The new_array iterator object: [object Array Iterator]

Example 2

The following is another example of the JavaScript TypedArray entries() method. Using this method, we are trying to retrieve a new object array iterator from this typed array [10, 20, 30, 40, 50]. We use the next().value on the object array iterator to retrieve a specific element.

<html>
<head>
   <title>JavaScript TypedArray entries() Method</title>
</head>
<body>
   <script>
      const T_array = new Uint8Array([10, 20, 30, 40, 50]);
      document.write("The original typed array: ", T_array);
      
      //using the entries() method
      let new_array = T_array.entries();
      document.write("<br>The new_array iterator object: ", new_array);
      document.write("<br>The new_array.next().value returns: ", new_array.next().value);
      
      //expected output 10.
   </script>    
</body>
</html>

Output

After executing the above program, it returns the key as 0 and values as 10.

The original typed array: 10,20,30,40,50
The new_array iterator object: [object Array Iterator]
The new_array.next().value returns: 0,10

Example 3

In this example, we use the for...of loop to iterate through each element of the object array iterator returned by the entries() method.

<html>
<head>
   <title>JavaScript TypedArray entries() Method</title>
</head>
<body>
   <script>
      const T_array = new Uint8Array([10, 20, 30, 40, 50]);
      document.write("The original typed array: ", T_array);      
      
      //using the entries() method
      let new_array = T_array.entries();
      document.write("<br>The object array iterator values: ");      
      
      //using for...of loop
      for(const i of new_array){
         document.write("<br>Kyes = ", i[0], " Values = ", i[1]);
      }
   </script>    
</body>
</html>

Output

Once the above program is executed, it returns the key-value pair of each element of the object array iterator as −

The original typed array: 10,20,30,40,50
The object array iterator values:
Kyes = 0 Values = 10
Kyes = 1 Values = 20
Kyes = 2 Values = 30
Kyes = 3 Values = 40
Kyes = 4 Values = 50
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