TypeError: Cannot read properties of null (reading 'parentNode')

Hi @stephanrauh

Occasionally we receive crash reports that look like this:

TypeError: Cannot read properties of null (reading 'parentNode')
  at webViewerWheel(/assets/pdf-viewer/viewer-2.16.451.min.js:44:61771)

We use ngx-extended-pdf-viewer in a popup and this error appears right after popup is closed.

Most probably it happens because some listeners are not yet removed while html node is already destroyed.

We tried the following hack in close event handler:

    protected close(result?: void) {
        // wait for scripts to load
        if (!this.componentInitialized && this.pdfSrc != null) {
            this.warn('PDF engine is not initialized yet');
            return;
        }

        // unbind offending event listeners
        const application = (window as any).PDFViewerApplication;
        const unbindWindowEvents = application?.unbindWindowEvents?.bind(application);
        if (typeof unbindWindowEvents === 'function') {
            unbindWindowEvents();
        } else {
            this.warn('unbindWindowEvents failed');
        }

        super.close(result);
    }

but crash report contains log entry unbindWindowEvents failed, it means that viewer is in some intermediate state when PDFViewerApplication is null but it is running.

It is minor issue but we would like to know what are possible options to avoid this error?

Version info

• Version of ngx-extended-pdf-viewer 15.2.0

Desktop (please complete the following information):

• Browser Chrome 108.0.0

[kemsky]

@stephanrauh it does work, I made obvious mistake in condition (typeof was missing), but now when error is corrected, everything works as expected. Since PDFViewerApplication is singleton, the correct fix in the library itself may be too convoluted so I’m not sure if it is worth it.

[stephanrauh]

Exposing a method allowing you to unbind the event listeners isn’t that much work, so it might be worth it. To be honest, documenting the feature is more work than implementing it. I wonder if I should add a page dedicated to popups to the showcase.