Extending Command

The command class is the one that provides all the utilities inside a command and prepares it to receive all the command metadata.

Handling errors

Within Seyfert, there are different types of errors, depending on how critical the problem is.

Run throw error

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import { Command, type CommandContext } from "seyfert";
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export class HandlingErrors extends Command {
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  async run(context: CommandContext) {
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    throw new Error("Error, ehm, lol player detected");
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  }
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  // This will reply with the error message above "Error, ehm, lol player detected"
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  async onRunError(context: CommandContext, error: unknown) {
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    context.client.logger.fatal(error);
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    await context.editOrReply({
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      content: error instanceof Error ? error.message : `Error: ${error}`
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    });
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  }
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}

Options throw error

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

Middleware return stop

When a middleware returns a stop, seyfert issues this error and stops the progress of the command to be handled.

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

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