import tiimPrivateSale from './ethereum/tiimPrivateSale';

...

submitPrivateSale = async (event) => {
    event.preventDefault();

    const {investor, value, bonus} = this.state;

    this.closeSaleForm();

    this.setState({privateSaleLoading: true});
    const accounts = await web3.eth.getAccounts();
    const owner = accounts[0];

    try {
      const txn = await tiimPrivateSale.methods
      .sendToken(investor, web3.utils.toWei(value, 'ether'), web3.utils.toWei(bonus, 'ether') )
      .send({from: owner});
    } catch (err) {
      console.log(err);
      alert("Could not send private sale cause error : `" + err.message + "`");
      this.setState({privateSaleLoading: false});
      return;
    }

    const balance = await tiimToken.methods.balanceOf(this.state.privateSaleAddress).call();
    this.setState({privateSaleTiimBalance: balance});
    this.setState({privateSaleLoading: false});
    this.resetSaleForm();
  }

...