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Extending Command

With seyfert you can handle errors in a organized way and you can handle errors in different ways depending on the error.

Run throw error

This is the most common error and it is thrown when throw an error in the run method.

import { Command, type CommandContext } from "seyfert";

export class HandlingErrors extends Command {
  async run(context: CommandContext) {
    throw new Error("Error, ehm, lol player detected");
  }

  // This replies with the error message above "Error, ehm, lol player detected"
  async onRunError(context: CommandContext, error: unknown) {
    context.client.logger.fatal(error);
    await context.editOrReply({
      content: error instanceof Error ? error.message : `Error: ${error}`
    });
  }
}

Options throw error

This error is thrown when an option fails in the value method.

import {
  Command,
  createStringOption,
  Options,
  type CommandContext,
  type OnOptionsReturnObject,
  type OKFunction
} from "seyfert";

@Options({
  url: createStringOption({
    description: 'how to be a gamer',
    value(data, ok: OKFunction<URL>, fail) {
        if (isUrl(data.value)) return ok(new URL(data.value));
        fail('expected a valid url'); // This will fire the onOptionsError method
    }
  })
})
export class HandlingErrors extends Command {
  // url: expected a valid url
  async onOptionsError(
    context: CommandContext,
    metadata: OnOptionsReturnObject
  ) {
    await context.editOrReply({
      content: Object.entries(metadata)
        .filter((_) => _[1].failed)
        .map((error) => `${error[0]}: ${error[1].value}`)
        .join("\n")
    });
  }
}

Middleware return stop

When a middleware returns a stop, seyfert issues this error and stops the progress on the command being handled.

export default createMiddleware(({ context, next, stop, pass }) => {
  if (!Devs.includes(context.author.id)) return stop("User is not a developer");
  next();
});

import { Command, Middlewares, type CommandContext } from "seyfert";

@Middlewares(["OnlyDev"])
export class HandlingErrors extends Command {
  async onMiddlewaresError(context: CommandContext, error: Error) {
    await context.editOrReply({
      //User is not a developer
      content: error.message
    });
  }
}