feat(CommandInteraction): add CommandInteractionOptionResolver

[memikri]

Please describe the changes this PR makes and why it should be merged:
This PR creates a new structure, CommandInteractionOptionResolver, which acts as a resolver for CommandInteraction options. This replaces the existing Collection<string, CommandInteractionOption> on CommandInteraction#options with the new class.

The new class will allow for easier usage and validation of command options. It also will serve as an additional check against users having mismatches between their option types and their execution code. This also allows for TypeScript users to access the properties in a cleaner and type-safe way without custom parsers or casting.

Example:

import { Client, Snowflake } from "discord.js";

const client = new Client({ intents: [] });

client.on("ready", async () => {
  const guild = await client.guilds.fetch(process.env.DISCORD_GUILD_ID as Snowflake);
  await guild.commands.create({
    name: "test",
    description: "test",
    options: [
      {
        name: "sub",
        description: "sub",
        type: "SUB_COMMAND",
        options: [
          {
            name: "bar",
            description: "bar",
            type: "INTEGER",
            required: true,
          },
          {
            name: "baz",
            description: "baz",
            type: "USER",
            required: false,
          },
        ],
      },
    ],
  });
});

client.on("interactionCreate", async (interaction) => {
  if (interaction.isCommand() && interaction.commandName === "test") {
    const sub = interaction.options.getSubCommand("sub");
    if (sub) {
      const bar = sub.getInteger("bar", true);
      const baz = sub.getUser("baz");
      await interaction.reply((bar * 2).toString() + " " + baz?.id);
    } else {
      await interaction.reply("Error: Invalid subcommand!");
    }
  }
});

client.login(process.env.DISCORD_TOKEN);

Status and versioning classification:

• Code changes have been tested against the Discord API, or there are no code changes
• I know how to update typings and have done so, or typings don't need updating
• This PR changes the library's interface (methods or parameters added)
• This PR includes breaking changes (methods removed or renamed, parameters moved or removed)

[memikri]

Conversation: https://canary.discord.com/channels/222078108977594368/682166281826598932/864223683799154698

[NotSugden]

suppose you could do [required=false] but I only thought this after I made all the review comments and im lazy

[memikri]

This may also close #5880

[ImRodry]

Can you make the name parameter in getSubCommand optional? A command has multiple subcommands but only one can be ran at once so it doesn’t make much sense to specify the name of the command since you’re not supposed to know what name that’s gonna be.

[memikri]

That's why getSubCommand can't be required. It is as intended. Here is an example:

async function run(interaction: CommandInteraction) {
  const subcommand1 = interaction.options.getSubCommand("sub1");
  const subcommand2 = interaction.options.getSubCommand("sub2");
  if (subcommand1) {
    const subarg1 = subcommand1.getInteger("subarg1");
    // etc.
  } else if (subcommand2) {
    const subarg2 = subcommand2.getUser("subarg2");
    // etc.
  }
}

[monbrey]

const subcommand1 = interaction.options.getSubCommand("sub1");
const subcommand2 = interaction.options.getSubCommand("sub2");

I don't think this captures what Rodry meant, nor does it really address #5880 if I still don't immediately know which subcommand was run. Why would I want to try to get both (or more) subcommands - you know it has to be one of them. I just want to get whichever one it is.

const subcommand = interaction.options.getSubCommand();
if (subcommand.name === "sub1") {
  const subarg = subcommand.getInteger("integer");
  // etc.
} else if (subcommand.name === "sub2") {
  const subarg = subcommand.getUser("user");
  // etc.
}

Stale

[ImRodry]

Collection.get() returns undefined when it doesn't find the specified key so I think this behavior should stay the same

[iCrawl]

I don't agree with changing the interface to return undefined rather than the current null

[ImRodry]

Actually, following the convo on the discord server let's make group and subcommand properties instead of methods