default props

src/client/js/components/BookmarkButton.jsx

@@ -58,20 +58,13 @@ class BookmarkButton extends React.Component {
       return <div></div>;
     }
 
-    const btnSizeClassName = this.props.size ? `btn-${this.props.size}` : 'btn-md';
-    const addedClassNames = [
-      this.state.bookmarked ? 'active' : '',
-      btnSizeClassName,
-    ];
-    const addedClassName = addedClassNames.join(' ');
-
     return (
       <button
         type="button"
         href="#"
         title="Bookmark"
         onClick={this.handleClick}
-        className={`btn btn-circle btn-outline-warning btn-bookmark border-0 ${addedClassName}`}
+        className={`btn btn-circle btn-outline-warning btn-bookmark border-0 ${`btn-${this.props.size}`} ${this.state.bookmarked && 'active'}`}
       >
         <i className="icon-star"></i>
       </button>
@@ -86,4 +79,8 @@ BookmarkButton.propTypes = {
   size: PropTypes.string,
 };
 
+BookmarkButton.defaultProps = {
+  size: 'md',
+};
+
 export default BookmarkButton;