await Archives | JS FAQ - JavaScript Guides Online

How to test asynchronous code in JavaScript

Mocking and controlling timers are essential techniques for effective asynchronous testing in JavaScript. By simulating complex dependencies and managing delays, developers can create reliable tests that isolate code and reduce flakiness. Utilizing libraries like Jest facilitates mocking functions and advancing timers, ensuring efficient test execution.

Fetch API and AJAX

How to use async await with fetch in JavaScript

Fetch API and AJAXasync, await, fetch, js fetch

Effective error handling with async/await and fetch is essential for robust applications. Fetch only rejects on network errors, so checking response statuses is crucial. Implement try/catch blocks for network failures and HTTP errors. Consider retry logic and use Promise.allSettled for handling multiple asynchronous operations gracefully.

Unit Testing: Jest

How to test asynchronous code with Jest

Unit Testing: Jestasync, await, jest, promises

Async and await in Jest enable clean asynchronous testing by returning promises that Jest automatically waits to resolve. Use try/catch for error handling or Jest’s rejects matcher for concise rejection tests. Combining await with Promise.all improves parallel execution and test efficiency.