Another new feature, import.meta, is making its way through the TC-39 committee, and is being implemented for Node.js 10.x. It is an object existing within the scope of an ES6 module providing some metadata about the module. See https://github.com/tc39/proposal-import-meta.
A partial implementation, supporting just import.meta.url, has landed in the Node.js source. Its use requires the --harmony-import-meta command-line flag. The content of import.meta.url is a fully qualified file: URL for the current module, such as file:///Users/david/chap10/notes/app.mjs.
Where this becomes important is that ES6 modules do not support the __dirname, __filename, and other global variables used historically in Node.js modules. The ...