Node.js + Discord.js：无法读取未定义的属性“类”

Question

I have a problem with variables. I am working on a Discord RPG bot, but ran into a problem with player data. When I start the bot up with the console and sent a message to build my stats, the console would return

C:\Users\willi\OneDrive\Desktop\discord-bot\homies.js:395
                    player[id].class = reply;
                                     ^

TypeError: Cannot set property 'class' of undefined

I use the below code. This is a fragment of the whole program. All files required by this exists.

const Discord = require('discord.js');
const { prefix, token } = require('./config.json');
const client = new Discord.Client();
const fs = require('fs');

const player = fs.readFileSync('user.json', 'utf-8');

client.on('message', message => {
    var id = message.author.id;

    if (player[id] === undefined) {
            player[id] = {
                username: message.author.username,
                class: undefined,
                xp: 0,
                lvl: 1,
                xpReq: 100 + this.lvl * 75,
                hp: 0,
                maxHp: 0,
                str: 0,
                def: 0,
                int: 0,
                dex: 0,
                luck: 0,
                mana: 0,
                maxMana: 0,
                equip: {
                    top: undefined,
                    bottom: undefined,
                    hand: undefined,
                    acc1: undefined,
                    acc2: undefined
                },
                spellcaster: undefined,
                spells: []
            };
            var authorVerifier = m => m.author.id === id;
            var classAnswer = message.channel.createMessageCollector(authorVerifier, { time: 300000, max: 1 });
            var classInterpreter = function(reply) {
                if (reply !== 'fighter' && reply !== 'adventurer' && reply !== 'mage'
                && reply !== 'healer' && reply !== 'rouge' && reply !== 'tank') {
                    return message.channel.send('That was not a valid class!');
                }
                else {
                    player[id].class = reply;
                    fs.writeFileSync('user.json', player[id], (err) => {
                        if (err) throw err;
                    });
                }
            }
        classAnswer.on('collect', m => classInterpreter(m.content));
    }
});

I tried replacing id with message.author.id , but to no avail. Please help!

Answer 1

You can solve it by passing the player array to the classInterpreter function, and use that to set player[id].class value.

classAnswer.on('collect', m => classInterpreter(m.content, player));