.entries()

Returns a new Array Iterator object that contains the key/value pairs for each index in the array.

Examples:

let fruits = ['apple', 'banana', 'mango'];
let entries = fruits.entries();
console.log(entries.next().value); // [0, 'apple']
console.log(entries.next().value); // [1, 'banana']

let names = ['Alice', 'Bob', 'Charlie'];
let nameEntries = names.entries();
for (let e of nameEntries) {
  console.log(e);
}
// [0, 'Alice']
// [1, 'Bob']
// [2, 'Charlie']