title: How can I get Coordinates of Points of Contour corners in OpenCV.js?
body: <p>I'm using OpenCV.js with JavaScript and trying to get points of an approxPolyDP return. Here is my code:</p>
  
  <pre><code>let src = cv.imread(imgElement);
  let contours = new cv.MatVector();
  let hierarchy = new cv.Mat();
  let poly = new cv.MatVector();
  
  cv.findContours(src, contours, hierarchy, cv.RETR_EXTERNAL, cv.CHAIN_APPROX_SIMPLE);
  
  let cnt = contours.get(0);
  
  cv.approxPolyDP(cnt, poly, 0.02 * peri, true);
  </code></pre>
  
  <p>That draws perfect with <code>drawContours()</code> function. But I want to get the coordinates of points of the corners. It's simple to get it on Python, but not JavaScript.</p>
  
  <p>How can I get the points' coordinates of corners?</p>