检查数组中是否存在 object 类型

Question

I have an abstract class that call Car.

    abstract class Vehicles {
}

I have more 3 classes,which inheritance Car:

class Car extends Vehicles {
}

class Motorcycle extends Vehicles {
}

class Truck extends Vehicles {
}

I want to make a random array that his type is Vehicles:

let vehicles1: Vehicles [] = new Array(2);

But i don't want repeat the same Vehicles type twice.(There will be no two cars for example) I can check every type the object that was created,but if i have 20 classes that extends Vehicles?

How i can to check if the object, was already created in array or not? but witout alot of if check? (typeof)

thank you.

Answer 1

You can use findIndex to insure there is no other items of the same type, here is an example of the function that adds a new item to the vehicles1 array but before that it tests for any existing items of the same type:

function addVehicle(vehicle) {
        const thisType = typeof vehicle;

        const index = vehicles1.findIndex(el => typeof el === thisType);
        if(index !== -1) {
            // that means there is no item of the same type, So you can add this one
        }
}