title: How can I remove all objects for specific key inside an array after fulfilling the condition?
body: <p>I've got an array(<em>options</em>) of objects where each of object also have an array(<em>answers</em>) with objects. In those object form <em>answers</em> array I've got objects with respondents. Now I'd like to delete respondent form <em>answers</em> if all of his answers are <em>null</em>.</p>
  
  <p>Array of objects:</p>
  
  <pre><code>options [
    {
      optionId: 1,
      answers: [
        {
          respondent: { id: 1, displayName: 'John Doe' },
          answer: null
        },
        {
          respondent: { id: 2, displayName: 'Jane Doe' },
          answer: true
        }
      ]
    },
    {
      optionId: 2,
      answers: [
        {
          respondent: { id: 1, displayName: 'John Doe' },
          answer: null
        },
        {
          respondent: { id: 2, displayName: 'Jane Doe' },
          answer: true
        }
      ]
    }
  ]
  </code></pre>
  
  <p>So basiclly in this case I want to achive to have: </p>
  
  <pre><code>options [
        {
          optionId: 1,
          answers: [
            {
              respondent: { id: 2, displayName: 'Jane Doe' },
              answer: true
            }
          ]
        },
        {
          optionId: 2,
          answers: [
            {
              respondent: { id: 2, displayName: 'Jane Doe' },
              answer: true
            }
          ]
        }
      ]
  </code></pre>
  
  <p>Because all of respondent's 1 answers were null.</p>
  
  <p>First I thought to use forEach() on option array to take those answers, and after this filter but I don't know how to make this condition for one respondent in different arrays.</p>