discord-command-parser

Basic parsing for messages received with discord.js OR eris.

Installation

$ yarn add discord-command-parser

or, with NPM

$ npm i discord-command-parser

Examples

Discord.js

import { parse } from "discord-command-parser";

bot.on("message", async (message) => {
  const parsed = parse(message, "!", { allowSpaceBeforeCommand: true });
  if (!parsed.success) return;
  if (parsed.command === "ping") return message.reply("Pong!");
});

Eris

import { parse } from "discord-command-parser";

bot.on("messageCreate", async (message) => {
  const parsed = parse(message, "!", { allowSpaceBeforeCommand: true });
  if (!parsed.success) return;
  if (parsed.command === "ping") return bot.createMessage(message.channelID, "Pong!");
});

Usage

---

parse(message, prefix [, options]): ParsedMessage

Parses a message for commands. prefix may be a string or an array of strings for command prefixes that the command must start with.

By default, this function checks to make sure that the message author is not a bot account. This can be overridden by setting options.allowBots to false.

options

• allowBots: boolean = false - By default, this function checks to make sure that the message author is not a bot account. Setting this to true will disable this check.
• allowSpaceBeforeCommand: boolean = false - Set this to true if you want the parser to be more forgiving of command prefixes (e.g. allowing "! ping" to work as well as "!ping" when the prefix is "!").
• ignorePrefixCase: boolean = false - If true, "A!ping" will behave the same as "a!ping". The bot will ignore the case of the prefix when checking for a match.

---

ParsedMessage

Represents the result of message parsing. This can be represent either a success or failure state. Check the success property to determine.

Common properties (success/failure)

• success: boolean - Whether the parsing succeeded and the message appears to be a valid command. Always remember to check this.
• error: string | undefined - On failure, this will detail which check failed for debugging purposes.
• message: Message - The message that was parsed.

Note: In the event of a failure, only the success, error, and message properties are defined.

Successful-only properties

• prefix: string - The prefix that the command starts with. Useful when using an array of prefixes.

• command: string - The command name that was parsed from the message (e.g. "ping" for a message of "!ping").

• arguments: string[] - The arguments (whitespace-delimited) that were passed after the command name. This also processes quoted parameters to allow for whitespace inside arguments (e.g. ["hello", "foo bar"] for the message "!say hello "foo bar"").

  Valid quote types are single ('), double ("), and codeblock (```).

  Note that Inline code (`) is not supported.

• body: string - The body of the message immediately following the command name (e.g. "hello world" for the message "!say hello world").

• reader: MessageArgumentReader - The MessageArgumentReader instance for this command. See the MessageArgumentReader section below.

TypeScript Note: a ParsedMessage can represent either an invalid result (FailedParsedMessage) or a successful result (SuccessfulParsedMessage). The result of parse() should be picked up by TypeScript just by checking the parsed.success value.

Additionally, the ParsedMessage classes are generic. Pass the discord.js or eris Message type to the generic field (e.g. ParsedMessage<Message>).

If you are using a library other than discord.js or eris, ensure that the Message type you use adheres to the BasicMessage interface in the source code.

---

MessageArgumentReader

An object-oriented way of sequentially parsing and checking arguments and is usually preferable over the ParsedMessage.arguments array.

For all "get" methods, the peek parameter will not advance to the next argument and will just return the current argument.

A Validator<T> is an optional function which accepts a parameter of type T and returns a boolean indicative of whether the value is valid. If a Validator returns false, then the invoking get___ function will return null.

getString(peek: boolean = false, v?: Validator<string>): string | null

Returns the next argument (or null if exhausted)

getInt(peek: boolean = false, v?: Validator<number>): number | null

Returns the next (safe) integer (or null if exhausted)

getFloat(peek: boolean = false, v?: Validator<number>): number | null

Returns the next (safe down to 2 decimal places) float (or null if exhausted)

getRemaining(peek: boolean = false, v?: Validator<string>): string | null

Gets all the remaining text. This advances the index to the end unless peek is true.

getUserID(peek: boolean = false, v?: Validator<string>): string | null

Advances the index (unless peek is true), and then tries to parse a valid user ID or user mention and returns the ID, if found, otherwise null.

getRoleID(peek: boolean = false, v?: Validator<string>): string | null

Similar to getUserID, but using role mention format (<@&123...>).

getChannelID(peek: boolean = false, v?: Validator<string>): string | null

Similar to getUserID, but using channel mention format (<#123...>).

seek(amount: number = 1): this

Safely increments or decrements the index. Useful for skipping arguments.

---

Contributing

If you wish to submit a PR with new or fixed feautres, make sure to create/modify test cases in tests/index.js and ensure that npm test works.

Please adhere to the code style that is managed by Prettier. If you use Visual Studio Code, you can install the Prettier extenstion.

Examples (TypeScript)

Basic usage:

import { parse } from "discord-command-parser";
import { Client, Message } from "discord.js";

const bot = new Client();

bot.on("message", async (message) => {
  const parsed = parse(message, "!", {
    allowSpaceBeforeCommand: true,
  });

  if (!parsed.success) return;

  if (message.command === "ping") return message.reply("Pong!");
});

bot.login("token");

MessageArgumentReader - "send" command

// ...
bot.on("message", async (message) => {
  // ...
  if (parsed.command === "send" || parsed.command === "dm") {
    const recipient = parsed.reader.getUserID();
    const content = parsed.reader.getRemaining();

    if (!recipient || !content) {
      return message.reply(`Usage: ${parsed.prefix}${parsed.command} <user> <message>`);
    }

    try {
      const user = await bot.users.fetch(recipient);
    } catch {
      return message.reply("Invalid recipient!");
    }

    try {
      await user.send(content);
    } catch {
      return message.reply("Could not DM user.");
    }

    return;
  }
});
// ...

License

This program is licensed under the MIT License. See the LICENSE file in the root of the project or https://opensource.org/licenses/MIT for more info.

Copyright © 2020 Brenden Campbell.