title: How to convert a JSON style object to a CSS string?
body: <p>I wanted to set my element's style as such:</p>
  
  <pre><code>this.refs.element.style = {
      ...this.props.style,
      background: 'blue',
  };
  </code></pre>
  
  <p>But apparently you can't use an object to set the ref's style. I have to use a CSS style string with <code>;</code> separating the <code>prop:values</code></p>
  
  <p>I'm aware that most people would set style in the render function, but for performance reasons, I can't repeatedly re-render.</p>