Cache message discord.js

Question

I would like to make some reaction roles. But for that, I have to cache messages which were sent before the bot started. I tried it with channel.messages.fetch, but that hasn't worked so far.

My current code:

client.on('messageReactionAdd', async(reaction, user) => {
    client.channels.cache.get("689034237672030230");
    channel.messages.fetch('708428887612194979');
    // When we receive a reaction we check if the reaction is partial or not
    if (reaction.partial) {
        // If the message this reaction belongs to was removed the fetching might result in an API error, which we need to handle
        try {
            await message.reaction.fetch();
        } catch (error) {
            console.log('Something went wrong when fetching the message: ', error);
            // Return as `reaction.message.author` may be undefined/null
            return;
        }
    }
    // Now the message has been cached and is fully available
    console.log(`${reaction.message.author}'s message "${reaction.message.id}" gained a reaction!`);
    // The reaction is now also fully available and the properties will be reflected accurately:
    console.log(`${reaction.count} user(s) have given the same reaction to this message!`);
});

Solution

What you have to do is first fetch the guild where the channel is in and then get the channel from the guild (so it returns a GuildChannel). Then fetch messages from there.

Full code would be:

client.on('ready', async () => {
  const guild = await client.guilds.fetch('guild-id-here');
  const channel = guild.channels.cache.get('channel-id-here');
  const message = await channel.messages.fetch('message-id-here');
});

client.on('message', message => {
  //rest of your code

});