GatsbyJS with Sanity: Example of adding additional `_raw` fields where needed

gatsby-node.js

const sourceRawField = fieldName => ({
  type: "JSON",
  resolve: (source, args, context, info) => {
    const data = source[fieldName]

    // Resolve top-level references in Portable Text
    if (data && Array.isArray(data)) {
      return data.map(block =>
        block._type === "reference"
          ? {
              _key: block._key,
              ...context.nodeModel.getNodeById({ id: block._ref }),
            }
          : block
      )
    }
    return data
  },
})

exports.createResolvers = ({ createResolvers }) => {
  createResolvers({
    // Repeat this for each type needed
    SanityBlogPost: {
      _rawContent: sourceRawField("content"),
    }
  })
}