It is good to have an understanding of how the language works. This includes the features of a language and their use cases and a decent understanding of the internals of the language so that your code can be efficient. I am not sure it is really important to know the far corner case oddities of a language. In ~4 years of using javascript I have never once encountered a situation where an oddity like the one you present or the famous .1 * .2 bug had any impact in my code or anyone I have worked with.
It is good to have an understanding of how the language works. This includes the features of a language and their use cases and a decent understanding of the internals of the language so that your code can be efficient. I am not sure it is really important to know the far corner case oddities of a language. In ~4 years of using javascript I have never once encountered a situation where an oddity like the one you present or the famous .1 * .2 bug had any impact in my code or anyone I have worked with.
Well put!