A Button, wrong way. 2.

Button.jsx

import React from 'react';
import cn from 'classnames';

type Props = {
  isSquare?: boolean,
  isRound?: boolean,
  isCircle?: boolean,
  isOutline?: boolean,
  color: string,
  children: string,
};

const Button = ({ children, isSquare, isRound, isCircle, isOutline, color }: Props) => {
  const c = (name) => `Button--${name}`;
  const classes = cn('Button', { 'Button--square': isSquare, /* etc */ });
  const colorStyles = isOutline ? { color, borderColor: color } : { backgroundColor: color };

  return (
    <button className={classes} style={{ ...colorStyles }}>
      {children}
    </button>
  );
};

export default Button;