Javascript Array entries()

 // defining an array named alphabets const alphabets = ["A", "B", "C"]; 
// array iterator object that contains // key-value pairs for each index in the array let iterator = alphabets.entries();
 // iterating through key-value pairs in the array for (let entry of iterator) { console.log(entry); } // Output: // [ 0, 'A' ] // [ 1, 'B' ] // [ 2, 'C' ]

entries() Syntax

The syntax of the entries() method is:

 arr.entries()

Here, arr is an array.

entries() Parameters

The entries() method does not take any parameters.

entries() Return Value

• Returns a new Array iterator object.

Note: The entries() method does not change the original array.

Example 1: Using entries() Method

 // defining an array const languages = ["Java", "C", "C++", "Python"]; 
// array iterator object that contains // key-value pairs for each index in the array let iterator = languages.entries();
 // looping through key-value pairs in the array for (let entry of iterator) { console.log(entry); }

Output

 [ 0, 'Java' ] [ 1, 'C' ] [ 2, 'C++' ] [ 3, 'Python' ]

In the above example, we have used the entries() method to get an Array iterator object of the key/value pair of each index in the language array.

We have then looped through iterator that prints the key/value pairs of each index.

Example 2: Using next() Method in Array Iterator Object

Array Iterator object has a built-in method called next() which is used to get the next value in the object.

Instead of looping through the iterator, we can get the key/value pairs using next().value. For example:

 // defining an array const symbols = ["#", "$", "*"]; 
// Array iterator object that holds key/value pairs let iterator = symbols.entries();
 // using built-in next() method in Array iterator object console.log(iterator.next().value); console.log(iterator.next().value); console.log(iterator.next().value);

Output

 [ 0, '#' ] [ 1, '$' ] [ 2, '*' ]

Also Read:

• JavaScript Array keys()