Create rectangle annotation using JavaScript

Here is an example of creating a rectangle annotation using JavaScript, but creating other types of annotations are similar.

WebViewer(...)
  .then(instance => {
    const { Annotations, annotationManager, documentViewer } = instance.Core;

    documentViewer.addEventListener('documentLoaded', () => {
      const rectangleAnnot = new Annotations.RectangleAnnotation();
      rectangleAnnot.PageNumber = 1;
      // values are in page coordinates with (0, 0) in the top left
      rectangleAnnot.X = 100;
      rectangleAnnot.Y = 150;
      rectangleAnnot.Width = 200;
      rectangleAnnot.Height = 50;
      rectangleAnnot.Author = annotationManager.getCurrentUser();

      annotationManager.addAnnotation(rectangleAnnot);
      // need to draw the annotation otherwise it won't show up until the page is refreshed
      annotationManager.redrawAnnotation(rectangleAnnot);
    })
  })