When are the onUnhandledException and onException callbacks triggered?

onUnhandledException: called when an exception is not handled by any try/catch or onException. It is typically used for logging crash information or reporting unknown errors.

onException: called by the system when an exception is explicitly thrown during a task or asynchronous operation, such as a failed network request or a data parsing error.

import { errorManager } from '@kit.AbilityKit';
import { BusinessError } from '@kit.BasicServicesKit';

let observer: errorManager.ErrorObserver = {
  onUnhandledException(errorMsg) {
    console.error('onUnhandledException, errorMsg: ', errorMsg);
  },
  onException(errorObj) {
    console.log('onException, name: ', errorObj.name);
    console.log('onException, message: ', errorObj.message);
    if (typeof (errorObj.stack) === 'string') {
      console.log('onException, stack: ', errorObj.stack);
    }
  }
};

try {
  errorManager.on('error', observer);
} catch (error) {
  console.error(`registerErrorObserver failed, error.code: ${(error as BusinessError).code}, error.message: ${(error as BusinessError).message}`);
}

The key difference is that onUnhandledException returns only the exception message, whereas onException provides the full exception object.

目录

When are the onUnhandledException and onException callbacks triggered?