JavaScript Modules
As websites and web applications become more complex, the more JavaScript that required. Keeping JavaScript in isolated scripts is no longer manageable. Therefore it because necessary to provide a way for splitting JavaScript into separate modules that can be imported when needed.
While the concept and practice of JavaScript modules has for over a decade, native browser support has only recently been achieved. Now JavaScript modules can be used within a web application without the need for Node.js or build tools like Webpack and Babel.