myStyled2.jsx

const myStyled = (TargetComponent) => (strs, ...exprs) => class extends React.Component {
  interpolateStyle() {
    const style = exprs.reduce((result, expr, index) => {
      const isFunc = typeof expr === 'function';
      const value = isFunc ? expr(this.props) : expr;
      
      return result + value + strs[index + 1];
    }, strs[0]);

    this.element.setAttribute('style', style);
  }

  componentDidMount() {
    this.interpolateStyle();
  }

  componentDidUpdate() {
    this.interpolateStyle();
  }

  render() {
    return <TargetComponent {...this.props} ref={element => this.element = element } />
  }
};

const primaryColor = 'coral';

const Button = myStyled('button')`
  background: ${({ primary }) => primary ? primaryColor : 'white'};
  color: ${({ primary }) => primary ? 'white' : primaryColor};
  padding: 0.25rem 1rem; 
  border: solid 2px ${primaryColor}; 
  border-radius: 3px;
  margin: 0.5rem;
  font-size: 1rem;
`;