The lack of a standard library is really the worst offender. Most of a given node_modules directory is filled with middleware to handle JS’s lack of everything.
Is that still a valid argument in 2024? The standard library has grown since the leftpad scandal. JS does have standard leftpad now.
It’s a genuine question, I no longer write Javascript for a living.
Compared to other languages it’s still very barebones – but admittedly some of the bloat is also because the JS world is kinda set in its ways. I still see people use jQuery for basic selector queries and SASS for basic CSS variables.
Another factor is that developers these days assume that users have fast unmetered connections. Loading 800 kB of minified gzipped JS from ten different domains is seen as no big deal. When the cost of adding piles of dependencies is considered nil there’s no impetus to avoid them.