libraries, frameworks, and modules - SelfishHellfish/JS_Ref GitHub Wiki
jquery
jquery is a library written in JS that offers many convenience/helper functions and methods. e.g. simplifies the use of AJAX.
angular2/reactJS
not just helper methods like jquery. creates a complete environment in which one can work - your entire app can be written using the commands and tools the framework provides, with the option of tweaking using your own JS code.
modularity
i.e. splitting up your project into multiple files (modules) that can be imported into the main app script and used. removes the need to have many imports in the html code and allows for easier modification and better organization
e.g. jspm allows for easy addition of libraries to a project, uses SystemJS to load/import all modules in the correct order (ensures no dependencies go unmet at import), and prepares the project for deployment, with bundling and modifications e.g. optimizing it by size etc.
more info on how to get started with modules