Fee

Executing a transaction requires a fee. This fee can originate from sources other than the transaction sender's account.

const account = await provider.getAccount();
const fee = new Amount(2000);
builder = builder
  .feeTransactionPayFromComponent(account.address, fee.getStringValue());

Under the hood, feeTransactionPayFromComponent creates an instruction that calls the pay_fee method on a component.

builder.addFeeInstruction({
  CallMethod: {
    component_address: componentAddress,
    method: "pay_fee",
    args: [maxFee],
  },
});

You might need to take this explicit route if the fee payment method is named something other than pay_fee.