third to last in array javascript code example

Example 1: javascript get second last element in array

const myNumbers = [100, 200, 300, 400, 500];
// option one
const seconLastNumber = myNumbers.slice(-2, -1)[0]) // 400

// option two
const seconLastNumber = myNumbers[numbers.length - 2]; // 400

Example 2: javascript get second last element of array

const numbers = ["one", "two", "three", "four"];
console.log(numbers[numbers.length - 2]);