Atom is quite the heavyweight compared to VSC, especially once you load in a few plugins.

Atleast about a year back when I used it, Atom quickly filled up about 8GB of RAM for a moderately sized project in Go plus all necessary plugins.

VSC is fast but no lightweight either and hogs some resources.

It's not inherently a problem with Javascript, usually it's some framework like React being misused as usual inducing a lot of GC activity on top of unnecessary memory bloat.