camping vqrno reshenie - js advanced exam

class SummerCamp{
    constructor(organizer, location){
        this.organizer = organizer;
        this.location = location;
        this.priceForTheCamp = {
            child: 150,
            student: 300,
            collegian: 500
        };
        this.listOfParticipants = [];
    }

    registerParticipant (name, condition, money){
        if (condition !== 'child' && condition !== 'student' && condition !== 'collegian') {
            throw new Error('Unsuccessful registration at the camp.');
        }
        if (this.listOfParticipants.some(partic => partic.name == name)) {
            return `The ${name} is already registered at the camp.`;
        }

        let price = -1;

        if (condition == 'child') {
            price = this.priceForTheCamp.child;
        }
        else if (condition == 'student') {
            price = this.priceForTheCamp.student;
        }
        else if (condition == 'collegian') {
            price = this.priceForTheCamp.collegian;
        }

        if (Number(money) < price) {
            return `The money is not enough to pay the stay at the camp.`;
        }

        let participan = {
            name: name,
            condition: condition,
            power: 100,
            wins: 0
        };

        this.listOfParticipants.push(participan);

        return  `The ${participan.name} was successfully registered.`
    }

    unregisterParticipant (name){
        if (!this.listOfParticipants.some(p => p.name == name)) {
            throw new Error(`The ${name} is not registered in the camp.`)
        }

        this.listOfParticipants = removeByAttr(this.listOfParticipants, 'name', name);

       function removeByAttr(arr, attr, value){
            var i = arr.length;
            while(i--){
               if( arr[i]
                   && arr[i].hasOwnProperty(attr)
                   && (arguments.length > 2 && arr[i][attr] === value ) ){

                   arr.splice(i,1);

               }
            }
            return arr;
        }

        return `The ${name} removed successfully.`;
    }

    timeToPlay (typeOfGame, participant1, participant2){
        if (typeOfGame == 'WaterBalloonFights') {

            let player1 = this.listOfParticipants.find(p => p.name == participant1);
            let player2 = this.listOfParticipants.find(p => p.name == participant2);

            if (!player1 || !player2) {
                throw new Error('Invalid entered name/s.')
            }

            if (player1.condition != player2.condition) {
                throw new Error('Choose players with equal condition.');
            }

            if (player1.power > player2.power) {
                player1.wins += 1;
                return  `The ${player1.name} is winner in the game ${typeOfGame}.`
            }
            if (player1.power < player2.power) {
                player2.wins += 1;
                return  `The ${player2.name} is winner in the game ${typeOfGame}.`
            }
            else {
                return `There is no winner.`;
            }
        }
        else if(typeOfGame == 'Battleship'){
            let player1 = this.listOfParticipants.find(p => p.name == participant1);

            if (!player1) {
                throw new Error('Invalid entered name/s.')
            }

            player1.power += 20;

            return `The ${player1.name} successfully completed the game ${typeOfGame}.`;
        }
    }

    toString () {

        this.listOfParticipants.sort((a, b) => b.power - a.power);

        let result = `${this.organizer} will take ${this.listOfParticipants.length} participants on camping to ${this.location}\n`;

        for (let index = 0; index < this.listOfParticipants.length; index++) {
            const player = this.listOfParticipants[index];
            result += `${player.name} - ${player.condition} - ${player.power} - ${player.wins}\n`
        }

        return result.trim();
    }
}

const summerCamp = new SummerCamp("Jane Austen", "Pancharevo Sofia 1137, Bulgaria");
console.log(summerCamp.registerParticipant("Petar Petarson", "student", 300));
console.log(summerCamp.timeToPlay("Battleship", "Petar Petarson"));
console.log(summerCamp.registerParticipant("Sara Dickinson", "child", 200));
//console.log(summerCamp.timeToPlay("WaterBalloonFights", "Petar Petarson", "Sara Dickinson"));
console.log(summerCamp.registerParticipant("Dimitur Kostov", "student", 300));
console.log(summerCamp.timeToPlay("WaterBalloonFights", "Petar Petarson", "Dimitur Kostov"));

console.log(summerCamp.toString());