It mostly boils down to the fact that javascript/nodejs does not ship with a standard library like every other language does. So every project has to include it

It mostly boils down to the fact that javascript/nodejs does not ship with a standard library like every other language does. So every project has to include its own copy of what passes as the standard library (A random smattering of npm modules). A casual peek into your node_modules folder will reveal packages such as left-pad, is-number, is-array etc. Stuff that is pre packaged into the runtime of any sane language. That's what makes up most of the bulk in any nodejs project.