This will be the final step in the LC process, where the buyer receives the goods and the seller receives the payment. Therefore, we define a closing transaction referencing the targeted LC and the reason behind the closure:

transaction Close {
  --> LetterOfCredit lc
  o String closeReason
}

event CloseEvent {
  --> LetterOfCredit lc
  o String closeReason
}

The letter status is set to CLOSED, and the step to 10:

/**
 * Close the LOC
 * @param {org.example.lc.Close} close - the Close transaction
 * @transaction
 */
async function close(closeRequest) { // eslint-disable-line no-unused-vars
    const factory = getFactory();
    const namespace = 'org.example.lc';

    let letter = closeRequest.lc;

    if (letter.status === 'SELL_RECEIVED_PAYMENT') {
        letter.status = 'CLOSED';
        letter.closeReason = closeRequest.closeReason;

        // update the status of the lc
        const assetRegistry = await getAssetRegistry(closeRequest.lc.getFullyQualifiedType());
        await assetRegistry.update(letter);

        // emit event
        const closeEvent = factory.newEvent(namespace, 'CloseEvent');
        closeEvent.lc = closeRequest.lc;
        closeEvent.closeReason = closeRequest.closeReason;
        emit(closeEvent);
    } else if (letter.status === 'CLOSED') {
        throw new Error('This letter of credit has already been closed');
    } else {
        throw new Error('Cannot close this letter of credit');
    }
}

This was the final part of our Chaincode. Now, let's deploy it in the Fabric network and check whether it works as expected.