title: overwrite getter of es6 class instance
body: <p>In this example I try to overwrite getter with cached value.</p>
  
  <p>it doesn't works.</p>
  
  <p>Is it possible to overwrite getter of a class instance?</p>
  
  <pre><code>class Module {
    constructor(id) {
      this.id = id
    }
    get element() {
      const elm = document.getElementById(id)
      if(!elm) throw new Error(`#${id} is not in document`)
      delete this.element;
      this.element = elm;
      return elm;
    }
  }
  </code></pre>