I think it stems from the language with it's simple untyped syntax and data-structures.
I like larger projects to be typed and my favorite language at the moment is definitely kotlin, but for quick prototyping I really like hacking things together in JS.
It's not just about being typed or not. I know huge, successful Ruby codebases which is not typed. Ruby ecosystem is just much more consistent and convenient than JS.
I like larger projects to be typed and my favorite language at the moment is definitely kotlin, but for quick prototyping I really like hacking things together in JS.