contract-invoking.js

  const startMint = async () => {
    setIsMinting(true);

    const user = await magic.user.getMetadata();

    contract.mint({
      from: user.publicAddress,
      id: license.offering.id,
      amount: values.amount,
      onTransactionCreated: transactionHash => {
        setField("transactionHash", transactionHash);
      },
      onComplete: () => setIsMinting(false)
    });
  };

  // ...
  useEffect(() => {
    biconomy
      .onEvent(biconomy.READY, async () => {
        setBiconomyReady(true);
      })
      .onEvent(biconomy.ERROR, (error, message) => {
        setFieldError("transactionHash", message);
      });
  }, []);
// ...