js array index of code example

Example 1: js array return only certain positions

const every_nth = (arr, nth) => arr.filter((e, i) => i % nth === nth - 1);
console.log(every_nth([1, 2, 3, 4, 5, 6], 1));
console.log(every_nth([1, 2, 3, 4, 5, 6], 2));
console.log(every_nth([1, 2, 3, 4, 5, 6], 3));
console.log(every_nth([1, 2, 3, 4, 5, 6], 4));

// OUTPUT

[1,2,3,4,5,6]
[2,4,6]
[3,6]
[4]

Example 2: js get index of item in array

array.indexOf("item");

Example 3: js array get index

var fruits = ["Banana", "Orange", "Apple", "Mango"];
return fruits.indexOf("Apple"); // Returns 2

Example 4: 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 5: how to get the index of an array in javascript

search = (arr, item) => { return arr.indexOf(item); }

Example 6: access index of array javascript

let first = fruits[0]
// Apple

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