var fruits = ['apple', 'orange', 'banana', 'pear'];

fruits.splice(3, 0, 'kiwi');

console.log(fruits);

// ["apple", "orange", "banana", "kiwi", "pear"]

​

var cars = ['porsche', 'ferrari', 'lambo', 'maserati'];

cars.splice(2, 1);

console.log(cars);

// ["porsche", "ferrari", "maserati"]

​

var planets = ['mars', 'saturn', 'jupiter', 'pluto'];

planets.splice(3, 1, 'uranus', 'mercury');

console.log(planets);

// ["mars", "saturn", "jupiter", "uranus", "mercury"]