Variable "$productSlug" is never used in operation "SingleProduct". Graphql error. Variables are not working in my Gatsby graphql queries

Question

I am getting this error: Variable "$productSlug" is never used in operation "SingleProduct".

I also use gatsby-source-wordpress to query fields from wordpress to gatsby. I also uninstalled Gatsby and re-installed it to see if it works in different versions, but it didn't.

I searched all over the internet and stack overflow for an answer, I really believe it must be a bug with Gatsby or gatsby-source-wordpress,

this is the code:

 const path = require("path"); const { createFilePath } = require(`gatsby-source-filesystem`); exports.onCreatePage = ({ page, actions }) => { const { createPage } = actions; if (page.path.match(/products/)) { page.context.layout = "ArchiveProduct"; createPage(page); } if (page.path.match(/products\/([^\/]+$)/)) { page.context.layout = "SingleProduct"; createPage(page); } }; exports.onCreateNode = ({ node, getNode, actions }) => { const { createNodeField } = actions; if (node.internal.type === `allWpProduct`) { const slug = createFilePath({ node, getNode, basePath: `pages` }); createNodeField({ node, name: `slug`, value: slug, }); } }; exports.createPages = async function ({ graphql, actions }) { const { data } = await graphql(` query SingleProduct { allWpProduct { nodes { uri slug id } } } `); data.allWpProduct.nodes.forEach((node) => { // const slug = node.slug; actions.createPage({ path: "/products/" + node.slug, component: path.resolve("./src/templates/SingleProduct.js"), context: { productSlug: node.slug, productId: node.id, layout: "SingleProduct", }, }); }); };

And this is the query:

 export const query = graphql` query SingleProduct($productSlug: String:) { wpProduct(slug: { eq: "$productSlug" }) { title slug link id date(formatString, "MMMM DD; YYYY") product { description price slug photo { localFile { childImageSharp { gatsbyImageData } } } } } } `;

Answer 1

Try the following:

export const query = graphql`
  query SingleProduct($productSlug: String!) {
    wpProduct(filter: {slug: { eq: "$productSlug" }}) {
      title
      slug
      link
      id
      date(formatString: "MMMM DD, YYYY")
      product {
        description
        price
        slug
        photo {
          localFile {
            childImageSharp {
              gatsbyImageData
            }
          }
        }
      }
    }
  }
`;

Your issue appears because $productSlug is lifted properly via context but never used in any sort of filtering action inside the query.

I'd recommend you check it before in the GraphiQL playground hardcoding the $productSlug to check the output.