chubbyts-throwable-to-error

Description

Converts any thrown value into an Error.

In JavaScript, throw accepts anything: strings, numbers, plain objects, null, undefined, … That is why TypeScript types a catch variable as unknown. throwableToError normalizes that value into a real Error, so the rest of your code (logging, error responses, cause chains) can rely on message and name being present.

Why use it

• Type safe: turns unknown into Error without unsafe as Error casts.
• Never throws: circular references, throwing toJSON / toString / getters and unserializable values are handled and reported as [unserializable] instead of crashing your error handler.
• Bounded output: messages longer than 2048 characters are truncated (suffix ...), so a huge thrown object can't flood your logs.
• Keeps real errors untouched: an Error (or subclass) is returned as is, the same instance with its original stack.
• Tiny: a single function, no dependencies.

Requirements

• node: >= 22

Installation

Through NPM as @chubbyts/chubbyts-throwable-to-error.

npm i @chubbyts/chubbyts-throwable-to-error@^2.4.1

Usage

import { throwableToError } from '@chubbyts/chubbyts-throwable-to-error/throwable-to-error';

try {
  throw { key: 'value' };
} catch (e) {
  const error = throwableToError(e);

  error.name; // 'object'
  error.message; // '{"key":"value"}'
}

Behavior

• Objects (and arrays) are serialized with JSON.stringify, all other values with String.
• The name is the typeof of the thrown value ('null' for null).
• The stack of a converted error is undefined: it would only point to throwableToError itself, not to the place where the value was thrown.

Copyright

2026 Dominik Zogg