What this plugin do?

This plugin will retrieve an image url defined as part of the frontmatter of a MDX or MarkdownRemark file and create a file node to be used with gatsby-plugin-image or gatsby-image

How to install

Just install as any other gatsby plugin!

$ npm install @matiasfha/gatsby-plugin-frontmatter-featured-image

or

$ yarn add gatsby-plugin-frontmatter-featured-image

then add this to your gatsby-config.js file as a plugin

{
  resolve: `@matiasfha/gatsby-plugin-frontmatter-featured-image,
  options: {
    image: 'featuredImage'
    }
}

How to configure the plugin

This plugin have only one configuration option, that is the image property. This property is used to let the plugin know what frontmatter attribute is used to store the image url

How to query?

This plugin will create a new "entry" when you are querying for your mdx data that will be named the same as the image property of the configuration, in this case featuredImage.

query MyQuery {
  allMdx {
    nodes {
      featuredImage {
        childImageSharp {
          gatsbyImageData
        }
      }
    }
  }
}

How it works?

It works by using the createResolvers gatsby api to create a new resolver on Mdx or MarkdownRemark files. On each node will create a new file node by using createRemoteFileNode from gatsby-source-filesystem this enable you to directly query and get gatsbyImageData.

Rationale

This was created out of the need of create nodes that are queryable to be used with gatsby-plugin-image when using the filesystem route api. With filesystem route api you have access to the body of the mdx file and also the frontmatter, but if you use an external image in frontmatter you cannot used as a dynamic image with gatsby-plugin-image This plugin solve that by created the required nodes.