Most of the 4 justifications mentioned sound like mitigations of otherwise bad design decisions. JavaScript in the browser went down this path for the longest time where new standards were introduced only to solve for stupid people instead of actually introducing new capabilities that were otherwise unachievable.
I do see some original benefits to a VFS though, bad application decisions aside, but they are exceedingly minor.
As an aside I think JavaScript would benefit from an in-memory database. This would be more of language enhancement than a Node.js enhancement. Imagine the extended application capabilities of an object/array store native to the language that takes queries using JS logic to return one or more objects/records. No SQL language and no third party databases for stuff that you don't want to keep in offline storage on a disk.
Why would you want a language enhancement for that, rather than just writing it in JS code? (or perhaps WASM)
Whether it is an object, array, something else, or a combination thereof is a design decision. It is not so much about the design of the structure, which should be determined by execution performance considerations, but how information is added, removed and retrieved. Gathering one or more records from a JSON object, or array index, by value of some child property somewhere in a descendant structure of the instance index always feels like a one-off based upon the shape of the data. That could just be a query which is more elegant to read and yet still achieves superior execution performance compared to a bunch of nested loops or string of function array methods.
The more structures you have in a given application and the larger those structures become in their schemas the more valuable a uniform storage and retrieval solution becomes.
Okay, what would your solution look like?
isn't really different fromsorted maps with log(n) access.
Like indexedDB but in Node?
> As an aside I think JavaScript would benefit from an in-memory database.
isn't that just global state, or do you mean you want that to be persistent?