text: import React from 'react';
  import PropTypes from 'prop-types';
  import Helmet from 'react-helmet';
  import useSiteMetadata from '../hooks/use-site-metadata';
  
  function SEO({ description, lang, meta, keywords, title }) {
    const siteMetadata = useSiteMetadata();
    const metaDescription = description || siteMetadata.description;
  
    return (
      <Helmet
        htmlAttributes={{
          lang,
        }}
        title={title || siteMetadata.title}
        titleTemplate={`%s | ${siteMetadata.title}`}
        meta={[
          {
            name: `description`,
            content: metaDescription,
          },
          {
            property: `og:title`,
            content: title,
          },
          {
            property: `og:description`,
            content: metaDescription,
          },
          {
            property: `og:type`,
            content: `website`,
          },
          {
            name: `twitter:card`,
            content: `summary`,
          },
          {
            name: `twitter:creator`,
            content: siteMetadata.author,
          },
          {
            name: `twitter:title`,
            content: title,
          },
          {
            name: `twitter:description`,
            content: metaDescription,
          },
        ]
          .concat(
            keywords.length > 0
              ? {
                  name: `keywords`,
                  content: keywords.join(`, `),
                }
              : []
          )
          .concat(meta)}
      />
    );
  }
  
  SEO.defaultProps = {
    lang: `en`,
    meta: [],
    keywords: [],
  };
  
  SEO.propTypes = {
    description: PropTypes.string,
    lang: PropTypes.string,
    meta: PropTypes.array,
    keywords: PropTypes.arrayOf(PropTypes.string),
    title: PropTypes.string.isRequired,
  };
  
  export default SEO;
  