how to define the index of an element in array javascript code example

Example 1: javasript array indexof

var array = [2, 9, 9];
array.indexOf(2);     // 0
array.indexOf(7);     // -1
array.indexOf(9, 2);  // 2
array.indexOf(2, -1); // -1
array.indexOf(2, -3); // 0

Example 2: access index of array javascript

let first = fruits[0]
// Apple

let last = fruits[fruits.length - 1]
// Banana