title: Javascript : What is the best way to detect combination of two keys in array of an object
body: <p>Lets say:</p>
  
  <pre><code>var person = [
      {"classKey": 1, "teacherKey": 1},
      {"classKey": 2, "teacherKey": 1},
      {"classKey": 2, "teacherKey": 1}
  ]  
  </code></pre>
  
  <p>How do i prevent the duplicated record to be added, or even how to remove the duplicated combinated pairs?</p>
  
  <p>Thank you</p>