error-kid

error-kid

A simple toolkit to work with custom errors. Definitely not a kid.

Installation

# yarn
yarn add error-kid

# pnpm
pnpm i error-kid

# npm
npm i error-kid

createErrorClass

Creates a new error class with predefined name and data type.

import { createErrorClass } from 'error-kid';

const UnknownError = createErrorClass('UnknownError');
UnknownError.name; // 'UnknownError'

By default, the created error class constructor accepts no arguments. It also passes nothing to the Error super constructor.

To change this behavior, define the arguments' type and provide the toSuper options function converting passed arguments to the Error super constructor.

Here is the example:

import { createErrorClass } from 'error-kid';

const UnknownError = createErrorClass<
  // Error name.
  'UnknownError',
  // Constructor arguments.
  [errorText: string, retriesCount: number, cause?: unknown]
>('UnknownError', {
  toSuper(errorText, retriesCount, cause) {
    // `Error` constructor requires the first argument
    // to be the error message. The second one is ErrorOptions,
    // containing the `cause` property.
    return [
      `Unknown error occurred. Retries count: ${retriesCount}. Error text: ${errorText}`,
      { cause },
    ];
  },
});

const error = new UnknownError('Ooopsie!', 3, new Error('Just because'));
error.message; // "Unknown error occurred. Retries count: 3. Error text: Ooopsie!"
error.cause; // Error('Just because')

If the custom error class must contain some additional data, consider using the second generic argument and provide the toData function converting constructor arguments to the defined type.

import { createErrorClass } from 'error-kid';

const TimeoutError = createErrorClass<
  'TimeoutError',
  { duration: number },
  [duration: number]
>('UnknownError', duration => ({ duration }), {
  toSuper(duration) {
    return [`Timed out: ${duration}ms`];
  },
});

const error = new TimeoutError(1000);
error.data; // { duration: 1000 }
error.message; // "Timed out: 1000ms"

// Or even without the third argument:
const AbortError = createErrorClass<
  'AbortError',
  { reason: unknown },
  [cause: unknown]
>('AbortError', cause => ({ reason: cause }));

const error2 = new AbortError(new Error('Just because'));
error2.data; // { reason: Error('Just because') }