Sending token via Ethereum smart contract interaction with redux-saga

eth-hot-wallet-send-token.js

// full source: https://github.com/PaulLaux/eth-hot-wallet/blob/master/app/containers/Header/saga.js#L203
export function* SendTransaction() {
  try {
    // ...
    const contractAddress = tokenInfo.contractAddress;
    const sendParams = { from: fromAddress, value: '0x0', gasPrice, gas: maxGasForTokenSend };
    const tokenAmount = amount * (10 ** tokenInfo.decimals); 

    function sendTokenPromise(tokenContractAddress, sendToAddress, sendAmount, params) {
      return new Promise((resolve, reject) => {
        const tokenContract = erc20Contract.at(tokenContractAddress);
        tokenContract.transfer.sendTransaction(sendToAddress, sendAmount, params, (err, sendTx) => {
          if (err) return reject(err);
          return resolve(sendTx);
        });
      });
    }
    const tx = yield call(sendTokenPromise, contractAddress, toAddress, tokenAmount, sendParams);
    // This saga will resume running after the transaction is sent and tx is returned by Ethereum node
    // ...
    yield put(sendTransactionSuccess(tx));
  } catch (err) {
    // ...
    yield put(sendTransactionError(errMsg));
}