TypeError undefined is not iterable in Telerik ReportViewer
Environment
| Product | Progress® Telerik® Reporting |
| Version | 19.1.25.521 |
Description
When attempting to preview a report using an HTML5-based report viewer, the following error appears in the console:
TypeError: undefined is not iterable (cannot read property Symbol(Symbol.iterator))
Cause
This issue occurs due to a breaking change in the latest version, where the report viewer is no longer fully initialized immediately after the $("#reportViewer1").telerik_ReportViewer call. As a result, subsequent calls like reportViewer.reportSource() immediately after initialization do not behave as expected.
Solution
Use the ready event to ensure the report viewer is fully initialized before setting the report source. For example, in the HTML5 report viewer, this would look as follows:
$("#reportViewer1")
.telerik_ReportViewer({
serviceUrl: "api/reports",
viewMode: telerikReportViewer.ViewModes.PRINT_PREVIEW,
scaleMode: telerikReportViewer.ScaleModes.SPECIFIC,
scale: 1,
enableAccessibility: false,
sendEmail: { enabled: false },
ready: function (e, args) {
const reportViewer = $("#reportViewer1").data("telerik_ReportViewer");
if (reportViewer !== undefined) {
reportViewer.reportSource({
report: 'Report1'
});
}
}
});