title: Using Jest property matchers on arrays of objects
body: <p>I am attempting to use Jest's new <a href="https://jestjs.io/docs/en/snapshot-testing#property-matchers" rel="noreferrer">Property Matcher</a> feature (since <a href="https://github.com/facebook/jest/blob/master/CHANGELOG.md#2300" rel="noreferrer">Jest 23.0.0</a>) to match on an array of objects that contain a generated field. I have tried putting both a plain object and a matcher definition using <code>expect.arrayContaining</code> and <code>expect.objectContaining</code> like I might when matching manually. Is there any way to do this currently?</p>
  
  <pre><code>const sportsBallPeople = [
    {
      createdAt: new Date(),
      name: 'That one famous guy from Cleveland'
    },
    {
      createdAt: new Date(),
      name: 'That tall guy'
    }
  ];
  expect(sportsBallPeople).toMatchSnapshot(&lt;something goes here&gt;);
  </code></pre>