import React from "react" ; import Helmet from "react-helmet" ; import { useStaticQuery , graphql } from "gatsby" ; const SEO = ( { description , lang , meta , title } ) => { const { site } = useStaticQuery ( graphql `
      query {
        site {
          siteMetadata {
            title
            description
            author
          }
        }
      }
    ` ) ; const metaDescription = description || site . siteMetadata . description ; return ( < Helmet htmlAttributes = { { land : lang || "en" , } } title = { title } titleTemplate = { `%s | ${ site . 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 : site . siteMetadata . author , } , { name : `twitter:title` , content : title , } , { name : `twitter:description` , content : metaDescription , } , ] . concat ( meta || [ ] ) } / > ) ; } ; interface SEOProps { description ? : string ; lang ? : string ; meta ? : [ { name : string ; content : string ; } ] ; title : string ; } export default SEO ;