fs.writeFile not writing to file unless run twice - node.js

Question

I'm trying to learn Node.js so I've been trying to write a simple Discord bot. It runs fine except when I try to write to a config file. It only writes to the file when I run the command twice or if another command is run right after it. I can't seem to figure out why it does that. It succeeds in posting a message in Discord after every command, but it's just the file that doesn't get updated. It doesn't output an error to the console either.
I have the code below and the config.json sample. Any help would be greatly appreciated.
config.json:
{
"ownerID": "1234567890",
"token": "insert-bot-token-here",
"prefix": "!",
"defaultStatus": "status-here"
}
const Discord = require("discord.js");
const client = new Discord.Client();
const fs = require("fs")
const config = require("./config.json");
client.on("ready", () => {
console.log("I am ready!");
client.user.setActivity(config.defaultStatus, {
type: 'WATCHING'
});
});
client.on("message", (message) => {
const args = message.content.slice(config.prefix.length).trim().split(/ +/g);
const command = args.shift().toLowerCase();
if (!message.content.startsWith(config.prefix) || message.author.bot) return;
if (command === "ping") {
message.channel.send("pong!");
} else
if (message.author.id !== config.ownerID) return message.reply("you must be the bot owner to run this command.");
let configData = JSON.stringify(config, null, 2);
// Command to change the prefix for commands
if (command === "prefix") {
let newPrefix = message.content.split(" ").slice(1, 2)[0];
config.prefix = newPrefix;
fs.writeFile("./config.json", configData, (err) => console.error);
message.channel.send("Prefix has been updated to \"" + newPrefix + "\"");
}
// Command to change the bot status
if (command === "status") {
let game = args.slice(0).join(" ");
client.user.setActivity(game, {
type: 'WATCHING'
});
message.channel.send("Status has been updated to \"" + game + "\"");
}
// Command to change the default bot status
if (command === "defaultstatus") {
let newStatus = args.slice(0).join(" ");
config.defaultStatus = newStatus;
client.user.setActivity(newStatus, {
type: 'WATCHING'
});
fs.writeFile("./config.json", configData, (err) => console.error);
message.channel.send("Default status has been updated to \"" + newStatus + "\"");
}
});
client.login(config.token);

Answer 1

That works only the second time because you're declaring configData before you change the config object.
configData = JSON.stringify(config, null, 2); //saves the config as a string
// you do all your stuff, including changing the prefix, for example
config.prefix = '-'; //this is stored in config, but not in configData
// then you write the file with the old data
fs.writeFile("./config.json", configData, (err) => console.error);
That causes the changes to be delayed every time.
You should create the configData after changing config:
...
config.prefix = '-'; // inside the command
...
let configData = JSON.stringify(config, null, 2);
fs.writeFile('./config.json', configData, err => console.error);