Add reaction to a specific message Discord.JS

Question

I am trying to create a command to add a reaction to a certain message.

The command is: /react "Channel-ID" "Message-ID" "Emoji"

But when running the command I get this error:

(node:4) UnhandledPromiseRejectionWarning: DiscordAPIError: Invalid Form Body:channel_id: Value "845345565700128788 <:XPLANE11:845383490286518322>" is not snowflake.

Is there any simple way of fixing this?

Thanks

client.on("message", message => {
        if (message.author.bot) return;
    
        let messageArray = message.content.split(" ");
        let command = messageArray[0];
        let channelid = messageArray.slice(1);
        let messageid = messageArray.slice(2);
        let emoji = messageArray.slice(3);
    
        if (message.channel.type === "dm") return;
    
        if (!message.content.startsWith('/')) return;
    
           if (command === '/react') {
    
            let memberrole = message.member.roles.cache.find(role => role.name === "CEO");
            if (!memberrole) return message.channel.send('Insufficiant Perms');
            
            message.client.channels.fetch(channelid.slice(1).join(" ")).then(channel => {
                channel.messages.fetch(messageid.slice(2).join(" ")).then(message => {
                    message.react(emoji.slice(3).join(" "));
                })
            })
          }});

For anyone wondering, this is the code that worked:

client.on('message', async (message) => {
    if (
      message.author.bot ||
      message.channel.type === 'dm' ||
      !message.content.startsWith(prefix)
    )
      return;
    
    const args = message.content.slice(prefix.length).split(/ +/);

    const command = args.shift().toLowerCase();
  
    if (command === 'react') {

      const [channelId, messageId, emoji] = args;
  

      if (!channelId)
        return message.channel.send(`You need to provide a channel ID`);

      const memberrole = message.member.roles.cache.find((role) => role.name === 'CEO');
      if (!memberrole) return message.channel.send('Insufficiant perms');
  
      try {
        const channel = await message.client.channels.fetch(channelId);
        if (!channel)
          return message.channel.send(`No channel found with the ID ${channelId}`);
  
        const msg = await channel.messages.fetch(messageId);
        if (!msg)
          return message.channel.send(`No message found with the ID ${messageId}`);
  
        msg.react(emoji);
      } catch (error) {
        console.log(error);
        message.channel.send('Oh-oh, there was an error...');
      }
    }
  });

Answer 1

The problem is you're using Array#slice() incorrectly. Array#slice() returns a shallow copy of a portion of an array into a new array. When you use messageArray.slice(1) you actually create a new array by chopping off the first element of messageArray , the command. For messageid you're chopping off the first two elements of messageArray , leaving you the message ID and the emoji. Check out the snippet below. If you run it, you can see the values of each variables:

 const message = { content: '/react 845345565700128700 845345565700128788 <:XPLANE11:845383490286518322>' } let messageArray = message.content.split(' '); let command = messageArray[0]; let channelid = messageArray.slice(1); let messageid = messageArray.slice(2); let emoji = messageArray.slice(3); console.log({ command, channelid, messageid, emoji })

So, at this moment, channelid is an array of three elements; the channel ID, the message ID, and the emoji. Inside the channels.fetch() method you once again create a new array by chopping off the first element and then join the rest by a single space. So, it becomes 845345565700128788 <:XPLANE11:845383490286518322> . Check out the snippet below:

 // messageArray.slice(1); const channelid = [ '845345565700128700', '845345565700128788', '<:XPLANE11:845383490286518322>', ] console.log(channelid.slice(1).join(' '))

If you check the value you try to fetch, it's exactly the one in your error message, Value "845345565700128788 <:XPLANE11:845383490286518322>" is not snowflake . It's not a valid snowflake. It's actually the message ID and the emoji in a single string.

To solve this, you could simply get the second element of the messageArray as the channelid , the third one as the messageid , etc:

let messageArray = message.content.split(' ');
let command = messageArray[0];
let channelid = messageArray[1];
let messageid = messageArray[2];
let emoji = messageArray[3];

You could also use array destructuring to get the same:

let messageArray = message.content.split(' ');
let [command, channelid, messageid, emoji] = messageArray;

And here is the full code:

// use a prefix variable
const prefix = '/';

client.on('message', async (message) => {
  if (
    message.author.bot ||
    message.channel.type === 'dm' ||
    !message.content.startsWith(prefix)
  )
    return;

  // create an args variable that slices off the prefix and splits it into an array
  const args = message.content.slice(prefix.length).split(/ +/);
  // create a command variable by taking the first element in the array
  // and removing it from args
  const command = args.shift().toLowerCase();

  if (command === 'react') {
    // destructure args
    const [channelId, messageId, emoji] = args;

    // check if there is channelId, messageId, and emoji provided
    // if not, send an error message
    if (!channelId)
      return message.channel.send(`You need to provide a channel ID`);

    // same with messageId and emoji
    // ...

    const memberrole = message.member.roles.cache.find((role) => role.name === 'CEO');
    if (!memberrole) return message.channel.send('Insufficiant perms');

    try {
      const channel = await message.client.channels.fetch(channelId);
      if (!channel)
        return message.channel.send(`No channel found with the ID ${channelId}`);

      const fetchedMessage = await channel.messages.fetch(messageId);
      if (!fetchedMessage)
        return message.channel.send(`No message found with the ID ${messageId}`);

      fetchedMessage.react(emoji);
    } catch (error) {
      console.log(error);
      message.channel.send('Oh-oh, there was an error...');
    }
  }
});