Inversion of control (IoC) techniques give developers a way to break out of traditional programming flow, and it offers them more flexibility and greater control over their code. Dependency injection, one form of IoC, is a pattern that aims to separate the concerns of constructing objects and using them. In this article, you’ll learn what dependency injection is, when you should use it, and what popular JavaScript frameworks it’s implemented in.

Testing code is the first step to making it secure. One of the best ways to do this is to use unit tests, ensuring that each of the smaller functions within an app behave as they should — especially when the app receives edge-case or invalid inputs, or inputs that are potentially harmful.

Developing and testing a frontend feature can be difficult, especially when the backend it depends on is not ready. This dependency on a backend API often slows down the development process. In scenarios like this, developing a mock API can save you a lot of time by allowing you to develop your feature independent of the backend, and make it easier to test and identify scenarios where your API might fail before it is ready.

When developers need to handle URLs in different forms for different purposes — such as browser history navigation, anchored targets, query parameters, and so on — we often turn to Java. However, its frequent use motivates attackers to exploit its vulnerabilities. This risk of exploitation is why we must implement URL validation in our JavaScript applications.