const lastLetterOfLastName = lastName[lastName.length-1];// assigns the last element of a string switch (lowercaseLetter) { // switch format case "a": console.log("A"); break; case "b": console.log("B"); break; } const fruits = ["Banana", "Orange", "Apple", "Mango"]; // checks if an item is included in the array fruits.includes("Banana", 3); delete ourDog.bark; // delete an objects properties myObj.hasOwnProperty("top"); myObj.hasOwnProperty("middle"); // check the object property if exist..returns true or false Math.floor(Math.random() * 20); // create random no from 0-19 Math.floor(Math.random() * (max - min + 1)) + min // with max and min