How to insert a javascript file in another javascript at build time file using a comment

Is there something on npm or in VS Code or anywhere that can bundle or concatenate Javascript files based on comments, like:

function myBigLibrary(){
    //@include util.js
    //@include init.js

    function privateFunc(){...}

    function publicFunc(){
      //@include somethingElse.js
      ...
    }

    
    
    return {
        init, publicFunc, etc
    }
}

Or something like that? I would think that such a thing is common when your javascript files get very large. All I can find are complicated things like webpack.