9 out of 10 JS developers I have worked with do not know how equality and object memory references work in JavaScript. They do not understand deep vs. shallow equality. They are barely aware of type coercion. When faced with a TypeScript error, their primary concern is shutting up the compiler. By any means necessary.
That sort of thing definitely happens, but the problem usually has very little to do with the choice of programming language. Front-end web development is the next generation's Visual Basic or PHP, the kind of software development that is easy to get into, but which as a result attracts a lot of people who have never really learned to program well. If you don't understand basic concepts like reference and value semantics, you're probably going to write bad code in any language, but you're also not particularly interesting from the point of view of what makes an effective language for a competent programmer.
That sort of thing definitely happens, but the problem usually has very little to do with the choice of programming language. Front-end web development is the next generation's Visual Basic or PHP, the kind of software development that is easy to get into, but which as a result attracts a lot of people who have never really learned to program well. If you don't understand basic concepts like reference and value semantics, you're probably going to write bad code in any language, but you're also not particularly interesting from the point of view of what makes an effective language for a competent programmer.