02Parking classes

class Parking {
    constructor(capacity) {
        this.capacity = capacity;
        this.vehicles = [];
        this.currentlyAdd = 0;
    }

    addCar(carModel, carNumber) {
        if (this.capacity <= this.vehicles.length) {
            throw new Error("Not enough parking space.");
        }
        this.vehicles.push({
            carModel: carModel,
                carNumber: carNumber,
                payed: false
            })
            this.currentlyAdd++;
            return `The ${carModel}, with a registration number ${carNumber}, parked.`
        }

        findCar(number) {
            return this.vehicles.find(y => y.carNumber === number);
        }

        removeCar(carNumber) {
            let neededCar = this.findCar(carNumber);
            if (!neededCar) {
                throw new Error("The car, you're looking for, is not found.");
            } else if (neededCar.payed === false) {
                throw new Error(`${carNumber} needs to pay before leaving the parking lot.`)
            }
            this.currentlyAdd--;
            this.vehicles = this.vehicles.filter(e => e !== neededCar);
            return `${carNumber} left the parking lot.`
        }

        pay(carNumber) {
            let neededCar = this.findCar(carNumber);
            if (!neededCar) {
                throw new Error(`${carNumber} is not in the parking lot.`)
            }
            if (neededCar.payed === true) {
                throw new Error(`${carNumber}'s driver has already payed his ticket.`)
            }
            neededCar.payed = true;
            return `${carNumber}'s driver successfully payed for his stay.`
        }
          getStatistics(carNumber) {
                let needCar = this.findCar(carNumber);
                if (carNumber) {
                    return `${needCar.carModel} == ${needCar.carNumber} - ${
                        needCar.payed ? `Has payed` : `Not payed`}`;
                }
        let result = [`The Parking Lot has ${ this.capacity - this.vehicles.length } empty spots left.`]
                // let result = [`The Parking Lot has ${this.capacity - this.vehicles.length} empty spots left`];

                this.vehicles
                    .sort((a, b) => {
                        return a.carModel.localeCompare(b.carModel);
                    })
                    .map((x) => {
                        result.push(`${x.carModel} == ${x.carNumber} - ${x.payed ? `Has payed` : `Not payed`}`);
                    });

                return result.join("\n");
            }

    }