React inline styles

Button.jsx

import React, { Component } from 'react';
import { baseStyle, loadingStyle } from './buttonStyle';

class Button extends Component {
  render () {
    return (
      <button
        style={{
          ...baseStyle,
          ...( this.props.isLoading ? loadingStyle : {}),
        }}
      >
        { this.props.text }
      </button>
    );
  }
}

buttonStyle.js

const baseStyle = {
  backgroundColor: blue,
};

const loadingStyle = {
  backgroundColor: grey,
};

export { baseStyle, loadingStyle };