title: Default props values in Storybook are not correct
body: <p>If I want to use default values for a component's property in React Storybook, it doesn't work. However, there are no issues in a React project.</p>
  <p>For example, if I have a <code>Button</code> component:</p>
  <pre><code>import React from &quot;react&quot;;
  
  const objs = { a: &quot;a&quot;, b: &quot;b&quot; };
  
  export const Button = ({ testProp = Object.keys(objs), text }) =&gt; {
    console.log({ objs });
    return &lt;button&gt;{text}&lt;/button&gt;;
  };
  </code></pre>
  <p><code>testProp</code> value is an array and this is <a href="https://codesandbox.io/s/inspiring-benz-35hn6?file=/src/Button.js" rel="nofollow noreferrer">correct</a>.</p>
  <p>This doesn't work in Storybook, where <code>testProp</code> value is <code>string</code></p>
  <p><a href="https://i.stack.imgur.com/1EYx3.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/1EYx3.png" alt="enter image description here" /></a></p>
  <p>I am not sure if I need to change some configuration or this is an issue in Storybook.</p>