The new version of the standard defines a programmatic API to work with modules. This is the so-called module loader API. It allows us to define and import modules, or configure the module loading.

Let's suppose we have the following module definition in the file app.js:

import { square } from './math';
 
export function main() { 
  console.log(square(2)); // 4 
} 

From the init.js file, we can programmatically load the app module and invoke its main function using:

System.import('./app') 
  .then(app => { 
    app.main(); 
  }) 
  .catch(error => { 
    console.log('Terrible error happened', error); 
  }); 

The global object System has a method called import that allows us to import modules using their identifier. In the preceding snippet, we import the module app defined in app.js. System.import returns a promise that could be resolved on success or rejected in case of an error. Once the promise is resolved...