Some of them are mentioned in the article: - Implicit type conversion - Javascript null handling - "all numbers are floats" Other languages have certain way

Some of them are mentioned in the article: - Implicit type conversion - Javascript null handling - "all numbers are floats" Other languages have certain ways of dealing with coding tasks that are quirky and weird as well. They are considered bad when they have unexpected side effects -- or cause bugs that are difficult to track down and diagnose. A common way to fight these issues is to use a linter -- something that runs when the code is built and warns you about lines of code that should most likely be changed or might be error prone.