The PDF Viewer library allows you to get the overlapped annotations on mouse click. Overlapped annotations on the selected annotation can be defined using the annotationCollection property of annotationSelect event.
Step 1: Follow the steps provided in the link to create simple PDF Viewer sample.
Step 2: The following code snippet explains how to get the overlapped annotations on mouse click.
// Get overlapped annotation collections.
viewer.annotationSelect =(args) =>{
console.log(args.annotationCollection);
}Find the Sample how to get the overlapped annotations on mouse click