JavaScript Immediately Invoked Function Expressions (IIFEs) are functions that are executed when they are initialized. An IIFE (pronounced “iffy”) can be initialized or defined to achieve a certain purpose. In this tutorial, you will learn about use cases for IIFEs and the benefits of using them over traditional functions. You will also write tests for your functions and integrate CI/CD for these tests.

JavaScript is one of the most widely used programming languages for creating dynamic, interactive websites. However, there may be instances where a function is not operating as intended because of a coding error while creating JavaScript projects. Therefore, the majority of developers hunt for JavaScript debugging tools to avoid problems and identify errors before execution.

Hopefully by now you’re taken your first sip of Elastic RUM, or real user monitoring, and see the power of searching through traces and the User Experience metrics to gain insights into how users actually use and experience your application. One issue you may have experienced is the challenge of finding the source of errors for minified JavaScript files.

The demands of a tight production schedule can make it difficult to produce consistent, readable, and concise code in the lead-up to a manual code review. This often makes the process stressful — if not outright dreaded. Standard tests are a critical part of development that verify that our code produces the expected outputs. But great tests don’t always lead to good code.

In the modern web, the JavaScript you write is often down-compiled using a compiler like Babel to make sure your JavaScript is compatible with older browsers or environments. In addition, if you are using TypeScript (like the Sentry SDK’s do) or something similar, you’ll have to transpile your TypeScript to JavaScript.