About

discord-message-handler is a module written to simplify message and command handling for discord.js bots and applications.

Table of Contents

• Installation
• Usage
  • Simple message handlers
  • Command handler
  • Commands with alias
  • Commands with usage info
  • Commands with regex validation
  • Commands with multiple validations
  • Command invocation deletion
  • Example handling messages across multiple files
  • Case sensitivity
  • Logging
• Contributing

Installation

Simply navigate to your project's folder and type npm install discord-message-handler --save on the command line.

Usage

To start using the module you must require it into you script like this (changed in 2.0)

Old style require:

const MessageHandler = require('discord-message-handler').MessageHandler;
const handler = new MessageHandler();

ES2015:

const { MessageHandler } = require('discord-message-handler');
const handler = new MessageHandler();

Typescript:

import { MessageHandler } from 'discord-message-handler';
const handler = new MessageHandler();

Define rules for the message handler (shown later in the next sections) then parse messages in the as they arrive:

client.on('message', message => {
    handler.handleMessage(message);
});

Simple message handlers

handler.whenMessageContainsWord("shrug").reply("¯\\_(ツ)_/¯");
handler.whenMessageContains("lol").sometimes(33).reply("kek"); // 33% chance
handler.whenMessageContainsExact("dota").replyOne(["volvo pls", "rip doto"]);
handler.whenMessageContainsOne(["br", "brazil"]).reply("huehue");
handler.whenMessageStartsWith("help").then(message => doSomething(message));

Command handler

handler.onCommand("/doit").do((args, rawArgs, message) => {
    message.channel.send(`Doing something for ${message.author}...`)
});

Commands with alias

handler.onCommand("/information").alias("/info").alias("/i").do((args) => {
    doSomething(args[0]);
});

Commands with usage info

handler 
    .onCommand("/info")
    .minArgs(2)
    .whenInvalid("Invalid command. Usage: /info <a> <b>")
    .do((args) => {
        doSomething(args[0]);
        doSomethingElse(args[1]);
    });

Commands with regex validation

handler
    .onCommand("!roll")
    .minArgs(1)
    .matches(/(\d+)?\s?d(6|20|100)/g)
    .whenInvalid("Invalid command. Usage: `!roll <number of dices> d<type of dice>`. Valid dices: d6, d20, d100")
    .do((args) => {
        // Dice roll logic
    })

Commands with multiple validations

In this version, you can chain commands and give whenInvalid an object with multiple parameters. They will be validated in the following order: 1. allowedChannels 2. minimumArguments 3. regularExpression

You can also pass in a flag when you want to send it to a user or a channel. Standard will be a reply in the channel.

handler
    .onCommand("!roll")
    .minArgs(1)
    .matches(/(\d+)?\s?d(6|20|100)/g)
    .allowedChannels(["45054768187"])
    .whenInvalid({
        sendToPlayer: true, 
        allowedChannels: "You are not allowed to use that in this channel.",
        minimumArgs: "Did you forget something?",
        regexPattern: "Please check your input."})
    .do((args) => {
        // Dice roll logic
    })

Command invocation deletion

You can automatically delete the message that triggered a command using the deleteInvocation method. The time argument is optional, and if absent the message will be deleted imediatelly.

// User's message will be deleted after 1500ms
handler.onCommand("/afk").deleteInvocation(1500).then((message) => {
    message.channel.send(`${message.author} is now AFK.`);
});

Example handling messages across multiple files

Consider you have the following structure:

├── commands
│   ├── greetings.js
│   └── helper.js
└── index.js

greetings.js:

module.exports.setup = function(handler) {
    handler.onCommand("/help").reply("<some helpful message>");
    handler.onCommand("/ping").reply("<actually calculate ping>");
}

helper.js:

const { MessageHandler } = require('discord-message-handler');

module.exports.setup = function(handler) {
    /* [Optional] You can recreate the handler using the parent context so your IDE will properly give out suggestions for the handler */
    const myhandler = new MessageHandler(handler);
    myhandler.whenMessageContainsWord("hey").reply("yo!");
    myhandler.whenMessageContainsWord("hi").reply("oh hi there :)");
}

index.js:

const { MessageHandler } = require('discord-message-handler');
const greetingsCommands = require('./commands/greetings');
const helperCommands = require('./commands/helper')

const handler = new MessageHandler();
greetingsCommands.setup(handler);
helperCommands.setup(handler);

// (...) code continues

Case sensitivity

In case you want message filters to be case sensitive you just need to call this function once:

handler.setCaseSensitive(true);

By default all message filters are case insensitive. (false)

Logging

To enable logging call handler.enableLogging() and pass a function to handle logs.

handler.enableLogging((filterType, filter, message) => {
    console.log(`${new Date().toISOString()} ${filterType}: ${filter} - "${message.content}"`);
});

Contributing

Feel free to send a pull request or open an issue if something is not working as intended or you belive could be better.