https://github.com/danielschaffer/ts-custom-error-shim

A TypeScript custom error shim that allows properly testing custom errors
https://github.com/danielschaffer/ts-custom-error-shim

custom-error testing typescript unit-testing

Last synced: about 2 months ago
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A TypeScript custom error shim that allows properly testing custom errors

• Host: GitHub
• URL: https://github.com/danielschaffer/ts-custom-error-shim
• Owner: DanielSchaffer
• License: mit
• Created: 2018-03-02T20:41:21.000Z (almost 7 years ago)
• Default Branch: master
• Last Pushed: 2023-04-23T17:02:56.000Z (almost 2 years ago)
• Last Synced: 2024-11-30T07:39:15.726Z (2 months ago)
• Topics: custom-error, testing, typescript, unit-testing
• Language: TypeScript
• Homepage:
• Size: 163 KB
• Stars: 1
• Watchers: 1
• Forks: 0
• Open Issues: 8
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# ts-custom-error

Extending `Error` does not work completely correctly with TypeScript

[starting with v2.1](https://github.com/Microsoft/TypeScript-wiki/blob/master/Breaking-Changes.md#extending-built-ins-like-error-array-and-map-may-no-longer-work).

While there isn't a completely function way of fixing this, this utility

seeks at least make unit testing custom errors a little easier. It works

by completely replacing the `Error` object on the global scope. This of

course means that using this on your actual build is likely a terrible

idea, but it will help you test your custom errors.

Note that this is not required for working with plain ES code, since

it works correctly with Node (v8) and most browsers. The problem is

specific to TypeScript.

# Installation

Install from NPM:

```bash

npm install ts-custom-error

```

# Usage

All that is needed for use is to import the package at the beginning of

your tests (before your actual code is imported). Since it replaces the

`Error` class, you do not need to change any of your custom errors to

subclass anything other than `Error`.

**Mocha:**

```bash

mocha --require ts-custom-error src/**/*.spec.ts

```

**Others:**

```typescript

import 'ts-custom-error';

```