The conversation metaphor in Chapter 2 implies that function parameters are basically the same as locally declared variables in the function scope. Keep an eye out for the following surprising scopes: In practice, these implied scopes don't often impact your program behavior, but it's still useful to know they're happening. Scopes are sometimes created in non-obvious places. It's long and deep in the weeds, so take your time and don't rush through everything here. This appendix is a bit like a collection of mini-blog posts that elaborate on various book topics. These discussions will also be more heavily influenced by my opinions than the main text was, so keep that in mind as you consume and consider what is presented. Wouldn't you rather be prepared for the inevitable bumps of off-roading? In other words, you won't get to spend all your time riding on the smooth happy path. Ultimately, you will encounter situations where something bubbles up from a piece you hadn't explored.

I believe it's better to be empowered by knowledge of how things work than to just gloss over details with assumptions and lack of curiosity. I understand and appreciate that perspective, even if I don't necessarily share it. My approach has been criticized as being impractical and counterproductive. Some people find diving too deeply into the nuanced corner cases and varying opinions creates nothing but noise and distraction-supposedly, developers are better served by sticking to the commonly-tread paths. This appendix is optional, supporting material. We will now explore a number of nuances and edges around many of the topics covered in the main text of this book. You Don't Know JS Yet: Scope & Closures - 2nd Edition Appendix A: Exploring Further

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