title: ES6 - declare a prototype method on a class with an import statement
body: <p>I am using ES6 classes. I want to be able to do this:</p>
  
  <pre><code>function Car(color) {
    this.color = color;
  };
  
  Car.prototype.getColor = require('./getColor');
  </code></pre>
  
  <p>Where get color is an exported function. i.e. I want to be able to import a function from an outside file and set is as a prototype method on the ES6 Class. This is the kind of syntax I am talking about:</p>
  
  <pre><code>class Car {
    constructor(color) {
      this.color = color;
    }
  
    getColor() {} // I want to import this function from './getColor', as above
  }
  </code></pre>
  
  <p>Is this doable?</p>