React Component "IconStack" using Font Awesome

IconStack.js

import React, { PropTypes } from 'react';

/* |Prop       |Type    |Default    |Description                                 |
 * |-----------|--------|-----------|--------------------------------------------|
 * |[children] |`node`  |`undefined`|Required: Child elements                    |
 * |[size]     |`string`|`undefined`|Increase size: 'lg', '2x', '3x', '4x', '5x' |
 * |[className]|`string`|`undefined`|Set a CSS class for extra styles            | */

const IconStack = ({
    className,
    size,
    children,
    ...props
}) => {
    const classNames = `
        fa-stack
        ${size ? `fa-${size}` : ''}
        ${className ? className : ''}
    `;
    return (
        <span {...props} className={classNames}>
            {children}
        </span>
    );
};

IconStack.propTypes = {
    className: PropTypes.string,
    size: PropTypes.oneOf(['lg', '2x', '3x', '4x', '5x']),
    children: PropTypes.node.isRequired
};

export default IconStack;