title: How to use ES6 Proxy in Typescript?
body: <p>I would like to try some things around Proxies, but i struggle to get the simplest form running. </p>
  
  <p>I have the following code</p>
  
  <pre><code>const myObj = {
    x: 'Hello',
  };
  
  const p = new Proxy(myObj, {
    get: (target, key) =&gt; {
      return key in target ? target[key] + ' World!' : 'nope';
    },
  });
  
  console.log(p.x);
  </code></pre>
  
  <p>And i get the following error, but i have no clue why and how to solve it:</p>
  
  <pre><code>index.ts:7:28 - error TS7053: Element implicitly has an 'any' type because expression of type 'string | number | symbol' can't be used to index type '{ x: string; }'.
    No index signature with a parameter of type 'string' was found on type '{ x: string; }'.
  
  7     return key in target ? target[key] + ' World!' : 'nope';
                               ~~~~~~~~~~~
  
  Found 1 error.
  </code></pre>
  
  <p>I think TS should be able to infer everything. What do i miss here?</p>