title: Jest expect object property value not to be object
body: <p>I have an array of 'flat' objects, i.e. properties whose values are either a string, number, null etc.</p>
  <pre><code>let myArray = [
      {
          prop1: 'string'
          prop2: 123
      },
      {
          prop1: 'string'
          prop2: 123
      },
  ]
  </code></pre>
  <p>In this case I don't care what the actual property keys are and ideally I don't want to know what they are in advance, i just want to check the property values are objects.</p>
  <p>The following would fail for example</p>
  <pre><code>let myArray = [
      {
          prop1: 'string'
          prop2: 123
      },
      {
          prop1: 'string'
          prop2: {
              prop3: true
          }
      },
  ]
  </code></pre>
  <p>How can I write this in a jest test?</p>
  <pre><code>expect(myArray).toEqual(
      expect.arrayContaining([
          expect.toBeObject()
          expect.objectValues.not.toBeObject    // What do I actually put here
      ])
  );
  </code></pre>
  <p>I am using jest extended.</p>