This project is a POC and miminal example of an error in hebcal/core (https://github.com/hebcal/hebcal-es6/) library in Angular, with devexpress (https://js.devexpress.com/Angular/Documentation/Guide/Angular_Components/Getting_Started/Add_DevExtreme_to_an_Angular_CLI_Application/)
git clone https://github.com/aepshtin/test-hebcal-dx
cd test-hebcal-dx
npm i
ng s
then open the browser at: http://localhost:4200/
and see the error in the console
Just comment out the Zman initilze and see how it works well