Description
in1 tells us if indices inside an array or
object have no associated element.
Syntax
const arr = ['a',,'b']
console.log(0 in arr) // true
console.log(1 in arr) // false
console.log(2 in arr) // true
console.log(arr[1]) // undefinedconst car = { make: "Honda", model: "Accord", year: 1998 };
console.log("make" in car); // true
delete car.make;
if ("make" in car === false) {
car.make = "Suzuki";
}
console.log(car.make); //Suzuki