In a reasonable language, you do something obviously wrong, and it throws an exception immediately, which gives you a stack trace that gives reasonable context for understanding what went wrong.
In JavaScript, the failure often happens silently: "foo" + 1 returns "foo1", {}.foo returns undefined, and program execution continues until it absolutely can't, finally failing far away from where the problem occurred. And when it does fail, it often fails in a callback deep within framework code with no clear, traceable execution path that leads back to the point where the error occurred. The errors have all the mysteriousness of C errors, without even the traceability.
The JavaScript community doesn't seem to be aware that there are better solutions, and seem happy with the way things are, even going so far as to use JavaScript on servers where far better tools exist. It seems that the only salvation that will come will be when mature tools exist on top of WebAssembly so that those of us who care about error reporting can use better toolchains.