how to act synchronously in nested function calls

something-something.js

  

  tryCredentials = () => {
    const encodedCredentials = encodeCredentials(this.state.username, this.state.password);
    // setEncodedCredentials is a func passed in props
    // I would like to wait on it without implementing promises everywhere
    this.props.setEncodedCredentials(encodedCredentials);
    // fetchProjects should be fired only after 'finished setting credentials' gets logged
    this.props.fetchProjects();
  };

  setEncodedCredentials = encodedCredentials => {
    console.log('setting encoded credentials');
    this.setState({
      ...this.state,
      encodedCredentials: encodedCredentials
    }, () => console.log('finished setting credentials'));
  };