@types/chai

What is @types/chai?

The @types/chai package provides TypeScript type definitions for Chai, a BDD / TDD assertion library for node and the browser. This allows developers to use Chai in TypeScript projects with type checking and IntelliSense support in code editors.

What are @types/chai's main functionalities?

Expect/Should Assertions

Provides fluent API for asserting facts about values in a readable manner. Supports both 'expect' and 'should' styles.

expect(foo).to.be.a('string');
expect(foo).to.equal('bar');
expect(foo).to.have.lengthOf(3);
should.exist(foo);
foo.should.be.a('string');
foo.should.equal('bar');

Assert Style

Enables a more classical assert style, similar to node's assert module but with more capabilities.

assert.typeOf(foo, 'string');
assert.equal(foo, 'bar');
assert.lengthOf(foo, 3);

Property Assertions

Allows asserting the existence of an object's property, optionally asserting its value or properties.

expect(foo).to.have.property('length').with.lengthOf(3);
foo.should.have.property('length').with.lengthOf(3);

Other packages similar to @types/chai

@types/jest

Provides TypeScript definitions for Jest, a testing framework with a focus on simplicity. While Jest comes with its own assertion library, it's more tightly integrated with its testing environment compared to Chai, which is assertion library agnostic.

@types/mocha

Offers TypeScript definitions for Mocha, a feature-rich JavaScript test framework running on Node.js and in the browser. Mocha itself is more about the test framework rather than assertions, and it's often used in combination with Chai.

@types/sinon

Supplies TypeScript definitions for Sinon, a standalone test spies, stubs, and mocks for JavaScript. While not an assertion library, Sinon is commonly used alongside Chai for behavior verification in tests.

README

Installation

npm install --save @types/chai

Summary

This package contains type definitions for chai (http://chaijs.com/).

Details

Files were exported from https://github.com/DefinitelyTyped/DefinitelyTyped/tree/master/types/chai.

Additional Details

• Last updated: Wed, 10 Feb 2021 18:23:12 GMT
• Dependencies: none
• Global values: Chai, chai

Credits

These definitions were written by Jed Mao, Bart van der Schoor, Andrew Brown, Olivier Chevet, Matt Wistrand, Josh Goldberg, Shaun Luttin, Gintautas Miselis, Satana Charuwichitratana, Erik Schierboom, Bogdan Paranytsia, CXuesong, and Joey Kilpatrick.