ES6 modules do not cover all the requirements to fully replace Node.js/CommonJS modules. One of the missing capabilities is being addressed with the Dynamic Import feature currently on its way through the TC-39 committee.

Support for dynamic imports landed in Node.js 9.7. See the documentation at: 
https://github.com/tc39/proposal-dynamic-import.

We'll use dynamic imports to solve an issue in Chapter 7, Data Storage and Retrieval, about dynamically choosing the module to load.  In normal usage of the require() statement, can use a simple string literal to specify the module name.  But it is also possible to use a string literal to compute the module name, like so:

// Node.js dynamically determined module loading
const moduleName = require(`../models/${process.env.MODEL_NAME}`);

We used this technique in earlier editions of this book to dynamically choose between several implementations of the same model API. The ES6 import statement does not support anything but a simple string literal, and therefore cannot compute the module specifier like this example.

With dynamic imports, we have an import() function where the module specifier is a regular string, letting us make a similar dynamic choice of module. Unlike the require() function, which is synchronous, import() is asynchronous, and returns a Promise. Hence, it's not a direct replacement for require() in that it's not terribly useful as a top-level function. You'll see how to use it in Chapter 7, Data Storage and Retrieval.

Perhaps the most important feature it brings is that CommonJS modules can use import() to load an ES6 module.