String interpolation/concat on Graphql Queries

[ThiagoMiranda]

Hi...
I'm trying to make a search and concatenate an variable with some surround string to work with the regex filter. How can I do that in Graphql? My goal is to wrap the $lang variable in / characters. Somehthing like that ( this don´t work ):

  query ContentByPath($slug: String!, $lang: String!) {
    site {
      siteMetadata {
        title
      }
    }
    markdownRemark(
      frontmatter: { slug: { eq: $slug } }, fileAbsolutePath: { regex: "/${$lang}/" }) {
      id
      htmlAst
      html
      frontmatter {
        section
        title
        date(formatString: "MMMM DD, YYYY")
      }
    }
  }

Is it possible?

Thanks

[m-allanson]

@ThiagoMiranda this isn't supported at the moment, but there's some discussion at #5069 and an RFC at gatsbyjs/rfcs#3.

[julionav]

I know this is closed but when googling how to do interpolation in gatsby this still shows up.

The workaround that I did for this is to construct the regex expression outside the graphql query.

In my case, it was inside createPages inside gatsby-node

context: {
  moduleRegex: `/${module}/`,
}

Then inside the query:

query($moduleRegex: String, $mdxId: String) {
    mdx(id: { eq: $mdxId }) {
      body
    }
    allFile(filter: { relativeDirectory: { regex: $moduleRegex } }) {
      nodes {
        name
      }
    }
}