> Turning to JavaScript, every method in Underscore.js lives in a single gigantic namespace.

This is really not a great example. Code written with heavy use of Underscore/Lodash is notoriously difficult to understand and maintain, because it is difficult to keep a mental model of all the pieces of the library and how they interact.

People mainly use these libraries when they come from a language with an extensive standard library, and want something familiar in JS. Experienced JS developers virtually never use them, for the above reason - it's bad for maintainability.

> This is a nice story, but the reality is that popular languages and libraries tend to expose API surfaces that are broad and shallow, not ones that are narrow and deep.

The unspoken assumption you're making here is that "what is popular, must also be the optimal thing to do". There's absolute mountains of evidence (eg. the tech hype cycle and ingrained cultural problems around NIHing) that suggest that this really isn't true.

Indeed, grabbing for broad and monolithic tools seems to be primarily a cultural thing, and people commonly do it because people commonly do it. It's ingrained culture.

This is especially painfully obvious in JS-land, which has all the tooling that's necessary to work with smaller, easier-to-reason-about, modular tools - but where I'm still spending half of my days in #Node.js trying to explain to people why it's a bad idea to try and replicate the Python standard library in JS. Yet those who take the advice seriously, consistently report that it has improved their development and maintenance process.

Likewise, dependencies in JS are a popular thing to complain about, but virtually all of the complaints are based on assumptions from how other languages work (where they would hold true), but that do not hold true for JS - and people rarely bother to try and learn more about how it actually works in JS. It's ingrained culture, not optimization.

In short, I don't think there's any merit to the claim that, paraphrased, "if everyone is doing it this way, it must be the better way". The referenced article makes a pretty good rational case, and it's a little odd to dismiss it purely based on "that's not what software looks like".

> Modern IDEs offer rich auto-completion with pop-up docs. This makes it much easier to look at the available list of fields and methods and choose the one that's appropriate.

Except it doesn't, because autocompletion is based on words, not on concepts. You still need to know what something is called, at least approximately, to get anything useful out of autocompletion. Otherwise it's just a big list of words. The reduction of concepts to smaller-scoped ones is precisely what helps there!

> Shallow APIs and big namespaces tend to favor easy lookup. Deep APIs where every type only has a handful of methods make you memorize them.

No, not really - it's actually the other way around.

Lookup is actually much easier in smaller-scoped APIs, because you can do a 'refined search' - instead of having to find-by-word the thing you're looking for in a huge list, you can start by selecting the appropriate API subset from a much smaller list, and then drill down into specific methods and such.

Big-scope APIs, on the other hand, require memorization; if you don't remember what a certain concept is called, you have no hope of ever finding it, short of a detour through some StackOverflow posts.