Errors that are returned from the Extensions API are custom Tableau error objects that extends the standard JavaScript error object.
In this section
The Extensions API wraps the standard error object with an errorCode property. You can use this error code for debugging or troubleshooting your extension. Any time you encounter an error when you are running your extension, you can look at this errorCode to determine the cause. See Error Codes.
As you create your extension, you want to be sure to catch potential error conditions. For example, you should validate user input and make use of try … catch statements. The Extensions API makes use of JavaScript promises. You can use the .catch method to field the errors that could be returned in the promise and any subsequent .then methods.
For an example of how to handle an extension dialog box error, see the UINamespace sample. The sample shows how you could handle the error condition that occurs if a user dismisses a modal dialog box (DialogClosedByUser). In this extension, the user is expected to click the Start Auto Refresh button, which saves the configuration settings and closes the dialog box, by calling the tableau.extensions.ui.closeDialog() method with the return payload. If a user clicks the dialog box control (the X in the upper-right corner) instead, the error occurs. The following snippet illustrates how you could handle this error:
tableau.extensions.ui.displayDialogAsync(args... ).then((args... ) => {
//
// code that sets up the extension in the modal dialog box
//
}).catch((error) => {
// One expected error condition is when the popup is closed by the user
// (meaning the user clicks the 'X' in the top right of the dialog).
// This can be checked for with:
switch(error.errorCode) {
case tableau.ErrorCodes.DialogClosedByUser:
console.log("Dialog was closed by user");
break;
default:
console.error(error.message);
}
});