The top 5 most common TypeScript issues were discovered through data analysis from SonarLint, highlighting a critical problem with creating and dropping objects immediately without being used, which can lead to confusing code, hard-to-read code, and bugs. This issue is not specific to TypeScript but also applies to JavaScript. To avoid this issue, developers should ensure that objects are assigned to variables or extract side effects from constructors to separate functions. SonarLint alerts on this issue and provides insights into potential problems, helping developers learn more about the issue and why it's a bad idea.