message: proper usage of let and const in center.js
diff: @@ -9,11 +9,11 @@ const assign = require('object-assign');
  const center = React.createClass({
  render() {
  - let {style, ...props} = this.props;
  - style = assign({}, style, {textAlign: 'center'});
  + const {style, ...props} = this.props;
  + const newStyle = assign({}, style, {textAlign: 'center'});
  return (
  - <div {...props} style={style}>{this.props.children}</div>
  + <div {...props} style={newStyle}>{this.props.children}</div>
  );
  },
  });
  