What is @types/chai-as-promised?
@types/chai-as-promised is a TypeScript type definition package for the chai-as-promised library, which extends Chai with assertions about promises. It allows you to write assertions for promises in a more readable and expressive way.
What are @types/chai-as-promised's main functionalities?
Eventual Fulfillment
This feature allows you to assert that a promise will eventually be fulfilled with a specific value.
const chai = require('chai');
const chaiAsPromised = require('chai-as-promised');
chai.use(chaiAsPromised);
const expect = chai.expect;
const promise = Promise.resolve(42);
expect(promise).to.eventually.equal(42);
Eventual Rejection
This feature allows you to assert that a promise will eventually be rejected with a specific error.
const chai = require('chai');
const chaiAsPromised = require('chai-as-promised');
chai.use(chaiAsPromised);
const expect = chai.expect;
const promise = Promise.reject(new Error('Something went wrong'));
expect(promise).to.be.rejectedWith('Something went wrong');
Combining with Other Chai Assertions
This feature allows you to combine promise assertions with other Chai assertions for more complex validations.
const chai = require('chai');
const chaiAsPromised = require('chai-as-promised');
chai.use(chaiAsPromised);
const expect = chai.expect;
const promise = Promise.resolve({ foo: 'bar' });
expect(promise).to.eventually.have.property('foo').that.equals('bar');
Other packages similar to @types/chai-as-promised
jest
Jest is a JavaScript testing framework that comes with built-in support for promises. It allows you to write tests for asynchronous code using async/await or promise-based syntax. Compared to chai-as-promised, Jest provides a more integrated testing experience with built-in matchers for promises.
sinon
Sinon is a library for creating spies, stubs, and mocks in JavaScript. While it is not specifically focused on promise assertions, it can be used in conjunction with other libraries like Chai to test asynchronous code. Sinon provides more comprehensive tools for mocking and spying on asynchronous functions compared to chai-as-promised.
mocha
Mocha is a feature-rich JavaScript test framework running on Node.js and in the browser. It allows you to use any assertion library, including Chai and chai-as-promised. Mocha itself does not provide promise assertions but can be used with chai-as-promised to achieve similar functionality.