title: ReactJs - Passing function as a prop. Warning: invalid prop
body: <p>I've got a working example of passing function from parent to child as a prop and then calling it from the child.</p>
  <p><a href="https://codesandbox.io/s/awesome-pond-y2h4v" rel="nofollow noreferrer">https://codesandbox.io/s/awesome-pond-y2h4v</a></p>
  <p>However, while it works fine , react doesnt like it and in the console it throws warning : Invalid value for prop <code>matrixfunc</code> on  tag.</p>
  <p>Any suggestions what could be the issue?</p>
  <p>Thanks</p>