Imports are handled differently in ES6 Modules than in CommonJS. We use import <name> from <file or package> to import in ES6
import { num1, num2, array, obj, add } from './exports';
Also, when we are importing a JavaScript file, Create-React-App will automatically look for the extension. So there is no need to add it.
// this will import the default variable from the file
import Subtraction from './imports';
import { num1 as myNumber1, num2 as myNumber2 } from './exports';
Go to Exports to see how to export.