[plugin-sitemap] filter undefined

Description

I recently got a the following error:

 ERROR #11321  PLUGIN

"gatsby-plugin-sitemap" threw an error while running the onPostBuild lifecycle:

Cannot read property 'filter' of undefined

At first I was confused, I wasn’t calling filter any where, I realized the plugin was probably using Array.prototype.filter() internally to filter urls in the exclude field. That’s when I realized the problem. My query was written:

allSitePage{
    nodes {
      path
      context {
        title
        modified
      }
    }
  }

While the plugin examples were written:

allSitePage{
    edges {
      node{
        path
        context {
          title
          modified
       }
     }
    }
  }

That meant the filter function didn’t exist because the data structure was different then expected by the plugin.

Steps to reproduce

skip the graphql edges node and use nodes in your allSitePages query

Expected result

I’d expect both data structures to work, should be easy enough to do some detection logic to figure out what structure was used and filter appropriately.

Environment

System: OS: Linux 5.3 Ubuntu 19.10 (Eoan Ermine) CPU: (8) x64 Intel® Core™ i7-8550U CPU @ 1.80GHz Shell: 5.0.3 - /bin/bash Binaries: Node: 12.14.1 - /tmp/yarn–1579323808977-0.10414995248476577/node Yarn: 1.21.1 - /tmp/yarn–1579323808977-0.10414995248476577/yarn npm: 6.13.4 - ~/.nvm/versions/node/v12.14.1/bin/npm Languages: Python: 2.7.17 - /usr/bin/python Browsers: Chrome: 79.0.3945.88 Firefox: 72.0.1 npmPackages: gatsby: ^2.18.3 => 2.18.22 gatsby-image: ^2.2.33 => 2.2.39 gatsby-plugin-manifest: ^2.2.29 => 2.2.37 gatsby-plugin-netlify: ^2.1.30 => 2.1.31 gatsby-plugin-offline: ^3.0.23 => 3.0.32 gatsby-plugin-preact: ^3.1.24 => 3.1.25 gatsby-plugin-purgecss: ^4.0.1 => 4.0.1 gatsby-plugin-react-helmet: ^3.1.15 => 3.1.21 gatsby-plugin-sass: ^2.1.26 => 2.1.27 gatsby-plugin-sharp: ^2.3.3 => 2.3.13 gatsby-plugin-sitemap: ^2.2.26 => 2.2.26 gatsby-source-filesystem: ^2.1.38 => 2.1.46 gatsby-source-graphql: ^2.1.24 => 2.1.31 gatsby-transformer-json: ^2.2.25 => 2.2.25 gatsby-transformer-sharp: ^2.3.5 => 2.3.13

[epgui]

@TylerBarnes I think the above description is pretty much on the nose. I’m getting the same issue when and only when I use nodes instead of edges.node.

[moonmeister]

For both of these, allowing a function to be passed in would be ideal.

//this is effectivly the default
resolveSiteUrl: (data) => {
return data.siteMetadata.siteUrl
}

//or in my case
resolveSiteUrl: () => siteUrl

filter could do the same thing, take a string and the internal filter is used against edges or nodes. If it takes a function it simply passes the results of the query, and maybe the glob tool into the function, and lets me do the rest.

PS: I might be able to do this work, just not for a couple weeks probably.