The text discusses the importance of code coverage and its benefits, such as identifying overlooked code execution routes, indicating good, tested code with high coverage, promoting the use of code coverage principles while developing unit tests, increasing programmers' confidence, determining which sections of the code have undergone testing, and suggesting some rewriting for better speed. SonarQube is a Java-based open-source tool that enables code coverage and static code analysis to evaluate the reliability and security of a program. It provides customizable reports and a dashboard to show the quality of the code in an app. The article guides readers on how to use SonarQube with a simple JavaScript application, including setting up a new project, installing SonarScanner, running tests, and configuring SonarQube.