类型错误：无法读取未定义的 discord js 的属性“first”

Question

I know I'm not the best at this stuff and I'm still learning but can anyone help me with my error, I know it's with my " let role = " and it's something to do with the ' = ' sign, I'm just not sure what to change it to.

if (!message.member.hasPermission('MANAGE_CHANNELS')) return message.reply(Embed3)
        if (!args[0]) return message.reply(Embed2)
        if (!message.mentions.channels.first()) return message.reply(Embed1)
        let role = message.guild.roles.cache.find(r => r.name = args[1]); //const role = message.mentions.roles.first
        if (!role) return message.reply(Embed4);

Current error is

TypeError: Cannot read property 'first' of undefined

I was following this guide , still not sure what to do though.

Any help is much appreciated, thanks and have a great day! :)

EDIT 1

In my index.js, I have this

--

client.on('message', message => {
    if (!message.content.startsWith(prefix) || message.author.bot) return;
    let args = message.content.substring(prefix.length).split(" ");
    const command = args.shift().toLowerCase();
    if (command === 'lock') {
        client.commands.get('lock').execute(message, args)

    } else if (command === 'unlock') {
        client.commands.get('unlock').execute(message, args)
    }
})

EDIT 2

Stops printing after this line

 if (channel.name.startsWith('🔒')) return message.reply(Embed5); console.log('All this works')

// STOPS PRINTING //
await message.mentions.channel.first.setName(`🔒${channel.name}`);  // If channel name is not changed it's being rate limited. 
            try {
                await channel.updateOverwrite(role, {
                    SEND_MESSAGES: false
                }); 
                message.channel.send(Embed6);
            } catch (err) {
                console.log(err);
                message.channel.send(Embed7); 
            }

        });
    }
}

Answer 1

So from what i read in the discord documentation

https://discord.js.org/#/docs/main/stable/class/Message?scrollTo=mentions https://discord.js.org/#/docs/main/stable/class/MessageMentions?scrollTo=channels

and what i have seen in your code:

It may be that the mentions might not have a channels property set if there is no mention in differen channels. Therefore you might need to check for that:

if (message.mentions.channels || !message.mentions.channels.first()) return message.reply(Embed1)

Also the find you use is strange:

let role = message.guild.roles.cache.find(r => r.name = args[1]);

This statement in the filter method will always set the name of the cache to args[1] and return the value. If args[1] is truthly, it will then return the first cache object. what you need is a compare in this place

let role = message.guild.roles.cache.find(r => r.name == args[1]); // does not check type
or
let role = message.guild.roles.cache.find(r => r.name === args[1]); // checks type

Edit 2:

You might also need to check the way you access the channel.first() prop. channel.first() is a method. If you want the result of this method be shure to call it.

And handle the promise correctly with the then method. Since setName will teurn a Promise you need to embrace it! https://discord.js.org/#/docs/main/stable/class/GuildChannel?scrollTo=setName

message.mentions.channels.first().setName(`🔒${channel.name}`).then((result) => { // If channel name is not changed it's being rate limited.
    try {
        await channel.updateOverwrite(role, {
            SEND_MESSAGES: false
        }); 
        message.channel.send(Embed6);
    } catch (err) {
        console.log(err);
        message.channel.send(Embed7); 
    }
});

Also be shure to coretly inline your code and to check your controll structure. If you are using VScode use the format method: How do you format code in Visual Studio Code (VSCode)

Please try to read up on async / await statements in modern JS. https://developer.mozilla.org/de/docs/Web/JavaScript/Reference/Statements/async_function

If you want to use await statement here, wrap it in a async function or use the then method to continue exec after processing.

Answer 2

I believe your mistake might have been attempting to find the first mentioned user in the channel. You would need to have used .fetch() for this. Make sure you respect your promise if you're using async!

If this isn't what you want and you simply want to find the first user that is mentioned in the message that the command is run on, you would need to use:

        if (!message.mentions.users.first()) return message.reply(Embed1)