The PDF Viewer library allows you to open the thumbnail pane programmatically using the openThumbnailPane() method.
The following steps are used to open the thumbnail.
Step 1: Follow the steps provided in the link to create a simple PDF Viewer sample.
Step 2: Use the following code snippet to open thumbnail.
<button (click)="openThumbnail()">Open Thumbnail Pane</button>
openThumbnail() {
var viewer = (<any>document.getElementById('pdfViewer')).ej2_instances[0];
// Open Thumbnail pane.
viewer.thumbnailViewModule.openThumbnailPane();
}
Find the sample, how to open the thumbnail pane programmatically