failCallback Property

export class ViewerLoadFromUriExample { 
    private _viewer: lt.LEADVIEW.Viewer = null; 
    private _demoUrl = 'https://demo.leadtools.com/images/pdf/leadtools.pdf'; 
 
    public constructor() { 
        if(lt.RasterSupport.kernelExpired) 
            lt.RasterSupport.setLicenseUri("https://demo.leadtools.com/licenses/js/LEADTOOLSEVAL.txt", "EVAL", null); 
    } 
 
    public run = (divID: string, setButtonId: string): void => { 
        const lv = new lt.LEADVIEW.Viewer(); 
 
        // Builds a new instance of LEADVIEW. 
        // For the full list of options that can be passed to the run method, 
        // refer to the settings JSON files that are included in the LEADVIEW demo application. 
        // Settings files can also be generated from the LEADVIEW application itself. 
        lv.run(null, { 
            'rootDivId': divID, 
            'showMainMenu': false, 
            'serviceHost': 'http://localhost:40000', // or wherever your host is 
            'servicePath': '', // the path to the root of the service, which is nothing for this example 
            'serviceApiPath': 'api', // Routing occurs at "/api", unless you change the routing in the DocumentsService 
        }); 
 
        this._viewer = lv; 
 
        document.getElementById(setButtonId).onclick = this.setCurrentDocument; 
    } 
 
    private setCurrentDocument = () => { 
        const loadOptions: lt.LEADVIEW.ILoadFromUriParams = { 
            url: this._demoUrl, 
            loadOptions: null, 
            loadingDialogCallback: null, 
            successCallback: (document: lt.Document.LEADDocument) => { 
                this._viewer.getDocumentViewer().setDocument(document); 
            }, 
            alwaysCallback: null, 
            failCallback: this.errorHandler 
        } 
 
        this._viewer.loadFromUri(loadOptions); 
    } 
 
    private errorHandler = (serviceError: lt.Document.ServiceError) => { 
        alert(`There was an error loading in the document. ${serviceError.message}`); 
    } 
}