This example (like purescript-tpay) depends on [decimal.js][decimal.js] so you need to install it (possibly by just running npm install).
To run this application you need your tpay id (your login id) and tpay code (on the bottom of the page in secure.tpay.com: Ustawienia → powiadomienia). You should also turn on "testing" payments there: Ustawienia → tryb testowy.
Probably the easiest way to test payment flow from local machine is to use serveo.net:
$ ssh -R 80:localhost:3000 serveo.netCopy domain which is printed on the console to this command:
$ nodemon server.js -- --tpay-id $TPAY_ID --tpay-secret $TPAY_CODE --base-url $DOMAINOpen a browser and test your payment workflow.