3_parking - js advanced exam

class Parking {

    constructor(capacity) {

        this.capacity = Number(capacity);

        this.vehicles = [];

    }



    addCar(carModel, carNumber) {

        if (this.capacity === this.vehicles.length) {

            throw new Error('Not enough parking space.');

        }



        this.vehicles.push({ carModel, carNumber, payed: false });



        return `The ${carModel}, with a registration number ${carNumber}, parked.`;

    }



    removeCar(carNumber) {

        let car = this.vehicles.find(x => x.carNumber === carNumber);



        if (!car) {

            throw new Error('The car, you\'re looking for, is not found.');

        }



        if (car.payed === false) {

            throw new Error(`${carNumber} needs to pay before leaving the parking lot.`);

        }



        let index = this.vehicles.indexOf(car);



        this.vehicles = this.vehicles.splice(index, 1);



        return `${carNumber} left the parking lot.`;

    }



    pay(carNumber) {

        let car = this.vehicles.find(x => x.carNumber === carNumber);



        if (!car) {

            throw new Error(`${carNumber} is not in the parking lot.`);

        }



        if (car.payed === true) {

            throw new Error(`${carNumber}'s driver has already payed his ticket.`);

        }



        car.payed = true;



        return `${carNumber}'s driver successfully payed for his stay.`;

    }



    getStatistics(carNumber) {

        if (carNumber !== undefined) {

            let car = this.vehicles.find(x => x.carNumber === carNumber);



            return `${car.carModel} == ${car.carNumber} - ${car.payed === true ? 'Has payed' : 'Not payed'}`;

        }



        let result = [];

        let count = 0;



        for (let i = 0; i < this.vehicles.length; i++) {

            count++;

        }



        result.push(`The Parking Lot has ${this.capacity - count} empty spots left.`);



        let sorted = this.vehicles.sort((a, b) => a.carModel.localeCompare(b.carModel));



        for (let car of sorted) {

            result.push(`${car.carModel} == ${car.carNumber} - ${car.payed === true ? 'Has payed' : 'Not payed'}`);

        }



        return result.join('\n');

    }

}