Function unknown2error

Why

try {
    throw anything;
} catch(e) {
    // e = anything
}

In JavaScript, for the variable e, there is no guarantee that e will be an Error object, although e should be an Error object, is generally considered as a best practice. To make it worse, in TypeScript, the e is treated as Unknown type in the strict mode, which enforces developers to write extra conditional statements in every catch block.

This package is designed to provide an elegant solution for this issue.

Installation

npm install @leismore/unknown2error

Test

npm test

Example

import { unknown2error } from '@leismore/unknown2error';

try {
    // ...
}
catch(error) {
    error = unknown2error(error); // error guaranteed to be an Error (or subclass) object
}

API

function unknown2error( error: any ): Error

The function converts anything into an object of Error (or subclasses) class. If error is an object of Error (or subclasses) class, it returns the original error object. With any other type, it will convert it into a string first and then an Error object will be created and returned by using the string as the message parameter.

Copyright

GNU Affero General Public License v3.0

Authors

• Kyle Chine (Initialised on 01 March 2022)

References

• MDN Web Docs: Error https://developer.mozilla.org/en-US/docs/web/javascript/reference/global_objects/error
• Announcing TypeScript 4.4 - Defaulting to the unknown Type in Catch Variables https://devblogs.microsoft.com/typescript/announcing-typescript-4-4/#use-unknown-catch-variables