earl

Ergonomic, modern and type-safe assertion library for TypeScript

Brings good parts of Jest back to good ol' Mocha

Features

• 💪 Use advanced assertions that are able to match whole ranges of values
• 🤖 Written in TypeScript with type-safety in mind
• 🎭 Type-safe, fully integrated mocks included
• ☕ Finally a modern assertion library for Mocha
• 📸 Snapshots can be easily created and updated with Earl
• 🔌 Tweak to your needs with plugins

Installation

npm install --save-dev earl

Example

import { expect } from 'earl'

const user = {
  name: 'John Doe',
  email: '[e-mail]',
  notificationCount: 5,
}

// This code fails to compile, and TypeScript provides this useful
// error message:
// Property 'notificationCount' is missing in type
// '{ name: string; email: any; }' but required in type 'User'.
expect(user).toEqual({
  name: 'John Doe',
  email: expect.a(String),
})

Docs

• Getting started
• API reference

License

Published under the MIT License. Copyright © 2023 L2BEAT.