Check class

A simple, stateless check for commands.

See AbstractCheck for a description of what a check is.

A Check is a simple check with no state, which validates CommandContexts with a single callback. The check succeeds if the callback returns true and fails if the callback returns false.

For example, to only allow users with "evrything" in their name to execute a command:

Check check = Check(
  (context) => context.user.username.contains('evrything'),
);

commands.addCommand(ChatCommand(
  'test',
  'A test command',
  (IChatContext context) => context.respond(MessageBuilder.content('Hi there!')),
  checks: [check],
));

commands.onCommandError.listen((error) {
  if (error is CheckFailedException) {
    error.context.respond(MessageBuilder.content("Sorry, you can't use that command!"));
  }
});

Since some checks are so common, nyxx_commands provides a set of in-built checks that also integrate with the Discord Slash Command Permissions API:

• GuildCheck, for checking if a command was invoked in a specific guild.

You might also be interested in:

• Check.any, Check.deny and Check.all, for modifying the behaviour of checks;
• AbstractCheck, which allows developers to create checks with state.