title: Good key props for a list of rating stars
body: <p>I have the following code to render 5 stars for a component. I want it always to be exactly 5 stars, but depending on the rating, the rest of the stars should be blank. I have the following code to achieve this.:</p>
  
  <pre><code>const stars = []
  for (let i = 0; i &lt; 5; i++){
    if (i &lt; Math.floor(rating)){
      stars.push(&lt;span className="feedback-star full"&gt;&lt;/span&gt;)
    } else {
      stars.push(&lt;span className="feedback-star blank"&gt;&lt;/span&gt;)
    }
  }
  </code></pre>
  
  <p>React is saying that I should have a unique key prop for each span. How should achieve this effectively? (I guess I could use new Date(), or Math.random(), but won't it be a lot of unnecessary operations on a list of over 100 feedbacks, each 5 stars?) </p>