TypeError undefined is not iterable in HTML5-based report viewers
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 19.1.25.521 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() will fail because the viewer instance is not yet ready.
Solution
Place logic that relies on the report viewer being fully initialized, such as the reportViewer.reportSource() calls, inside the ready event handler instead. 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'
});
}
}
});