discord.js/docs/examples/attachments.md

Sending Attachments

In here you'll see a few examples showing how you can send an attachment using discord.js.

Sending an attachment using a URL

There are a few ways you can do this, but we'll show you the easiest.

The following examples use MessageAttachment.

// Extract the required classes from the discord.js module
const { Client, MessageAttachment } = require('discord.js');

// Create an instance of a Discord client
const client = new Client();

/**
 * The ready event is vital, it means that only _after_ this will your bot start reacting to information
 * received from Discord
 */
client.on('ready', () => {
  console.log('I am ready!');
});

client.on('message', message => {
  // If the message is '!rip'
  if (message.content === '!rip') {
    // Create the attachment using MessageAttachment
    const attachment = new MessageAttachment('https://i.imgur.com/w3duR07.png');
    // Send the attachment in the message channel
    message.channel.send(attachment);
  }
});

// Log our bot in using the token from https://discord.com/developers/applications/me
client.login('your token here');

And here is the result:

But what if you want to send an attachment with a message content? Fear not, for it is easy to do that too! We'll recommend reading the TextChannel's "send" function documentation to see what other options are available.

// Extract the required classes from the discord.js module
const { Client, MessageAttachment } = require('discord.js');

// Create an instance of a Discord client
const client = new Client();

/**
 * The ready event is vital, it means that only _after_ this will your bot start reacting to information
 * received from Discord
 */
client.on('ready', () => {
  console.log('I am ready!');
});

client.on('message', message => {
  // If the message is '!rip'
  if (message.content === '!rip') {
    // Create the attachment using MessageAttachment
    const attachment = new MessageAttachment('https://i.imgur.com/w3duR07.png');
    // Send the attachment in the message channel with a content
    message.channel.send(`${message.author},`, attachment);
  }
});

// Log our bot in using the token from https://discord.com/developers/applications/me
client.login('your token here');

And here's the result of this one:

Sending a local file or buffer

Sending a local file isn't hard either! We'll be using MessageAttachment for these examples too.

// Extract the required classes from the discord.js module
const { Client, MessageAttachment } = require('discord.js');

// Create an instance of a Discord client
const client = new Client();

/**
 * The ready event is vital, it means that only _after_ this will your bot start reacting to information
 * received from Discord
 */
client.on('ready', () => {
  console.log('I am ready!');
});

client.on('message', message => {
  // If the message is '!rip'
  if (message.content === '!rip') {
    // Create the attachment using MessageAttachment
    const attachment = new MessageAttachment('./rip.png');
    // Send the attachment in the message channel with a content
    message.channel.send(`${message.author},`, attachment);
  }
});

// Log our bot in using the token from https://discord.com/developers/applications/me
client.login('your token here');

The results are the same as the URL examples:

But what if you have a buffer from an image? Or a text document? Well, it's the same as sending a local file or a URL!

In the following example, we'll be getting the buffer from a memes.txt file, and send it in the message channel. You can use any buffer you want, and send it. Just make sure to overwrite the filename if it isn't an image!

// Extract the required classes from the discord.js module
const { Client, MessageAttachment } = require('discord.js');

// Import the native fs module
const fs = require('fs');

// Create an instance of a Discord client
const client = new Client();

/**
 * The ready event is vital, it means that only _after_ this will your bot start reacting to information
 * received from Discord
 */
client.on('ready', () => {
  console.log('I am ready!');
});

client.on('message', message => {
  // If the message is '!memes'
  if (message.content === '!memes') {
    // Get the buffer from the 'memes.txt', assuming that the file exists
    const buffer = fs.readFileSync('./memes.txt');

    /**
     * Create the attachment using MessageAttachment,
     * overwritting the default file name to 'memes.txt'
     * Read more about it over at
     * http://discord.js.org/#/docs/main/master/class/MessageAttachment
     */
    const attachment = new MessageAttachment(buffer, 'memes.txt');
    // Send the attachment in the message channel with a content
    message.channel.send(`${message.author}, here are your memes!`, attachment);
  }
});

// Log our bot in using the token from https://discord.com/developers/applications/me
client.login('your token here');

And of course, the results are: