title: Why am I getting a warning of not having a unique key?
body: <p>This is my render</p>
  
  <pre><code>render() {
      let products = this.state.products  
      return (
        &lt;ul&gt;
          {products.map((product, index) =&gt; Product({ key: index, product: product }))}          
        &lt;/ul&gt;
      );
    }
  </code></pre>
  
  <p>I am using a unique key, and still get the warning </p>
  
  <blockquote>
    <p>Warning: Each child in an array or iterator should have a unique "key"
    prop.</p>
  </blockquote>