event documentAdded(
    uint id
);

function sendDocument(
    string memory _ipfsLocation,
    uint256 _uploadDate
)
public
{
    documentCount ++;
    ListOfDocuments[documentCount] = documentStore(documentCount, _ipfsLocation, msg.sender, _uploadDate);
    emit documentAdded(documentCount);
}

var event = storehash.events.documentAdded()

    event.watch(
        function(error, result) {
            if (!error)
                this.setState({idForBlockchain: result.args.id.toString()})
        }
    );


    //call the smart contract method to create a new document
    const documentId = await storehash.methods.sendDocument(this.state.IPFSlink, newDate).send({from: this.state.account})