JavaScript All-in-One For Dummies

Chapter 3

Testing Your JavaScript

IN THIS CHAPTER

Using ESLint

Debugging JavaScript in Chrome

Testing with Jest

Testing React components

“Testing — we will never do enough of it.”

—GREG LEMOND

Testing is considered the fourth phase of the systems development life cycle (SDLC), but it starts much earlier in the process. In fact, testing is an important tool throughout the software development process. You might start your journey as a programmer by doing only informal and ad hoc manual testing — for example, opening the application and clicking around to see whether it works. Or you might put a console.log statement in your code to check the value of a variable.

As your programming skills mature, you'll use tools that will make your testing easier or even allow you to make fewer mistakes in the first place.

A professional developer must always be considering testing and should make use of an automated testing framework to make tests repeatable. Automated testing has many benefits, from ensuring that the new code works to testing that it doesn't break something else and even to planning ...