toMap() bug?

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1

I’m loving DatoCMS and mostly been cruising along developing with it, but I’ve been pulling my hair out trying to solve a recent problem and I think I finally diagnosed it as maybe a bug?

I’m using Hugo with DatoCMS and have my config file set up to output .md files in yaml format. One example:

root.directory("content/exhibitions", (dir) => {
    dato.exhibitions.forEach((exhibition) => {
      dir.createPost(`${exhibition.slug}.md`, "yaml", {
        frontmatter: {
          title: exhibition.title,
          slug: exhibition.slug,
          exhibition_type: exhibition.exhibitionType,
          exhibition_space: exhibition.exhibitionSpace,
          opening_date: exhibition.openingDate,
          closing_date: exhibition.closingDate,
          gallery_artists: exhibition.galleryArtists.toMap(),
          other_artists: exhibition.otherArtists.toMap(),
          exhibition_images: exhibition.exhibitionImages.toMap(),
          main_image: exhibition.image.toMap()
        },
      });
    })
  });

Which outputs the .md file as expected and I have no trouble working with the data:

title: Exhibition 1
slug: exhibition-1
exhibition_type: Solo
exhibition_space: Downstairs
opening_date: 2021-10-05T00:00:00.000Z
closing_date: 2021-12-24T00:00:00.000Z
gallery_artists:
  - id: '54674262'
    itemType: artist
    updatedAt: '2021-08-31T14:14:06.952Z'
    createdAt: '2021-08-30T16:36:01.502Z'
    groupExhibitions:
      - id: '54674258'
        itemType: group_exhibition
        updatedAt: '2021-08-31T02:53:16.562Z'
        createdAt: '2021-08-30T16:36:01.467Z'
        exhibition: My Frontyard
        year: '2021'

        [...]

Then later in the config, I have the following block:

  root.directory("content/news", (dir) => {
    dir.createPost(`news.md`, "yaml", {
      frontmatter: {
        article: dato.news.article.toMap()
      },
    });
  });

But when that outputs the data related to “article” in a map, it formats it as follows:

article:
  - id: '55007998'
    itemType: article
    updatedAt: '2021-09-01T14:33:38.886Z'
    createdAt: '2021-09-01T14:33:38.882Z'
    slug: highlights-from-nada-new-york
    artists:
      id: '54674262'
      itemType: artist
      updatedAt: '2021-08-31T14:14:06.952Z'
      createdAt: '2021-08-30T16:36:01.502Z'

      [...]

Note that in the second map, the data below “artists” does not lead with the dash. This makes that information inaccessible via Hugo. It throws the error: can't evaluate field lastName in type interface {}

If I manually reformat the markdown file to the following, adding the dash and an extra tab:

article:
  - id: '55007998'
    itemType: article
    updatedAt: '2021-09-01T14:33:38.886Z'
    createdAt: '2021-09-01T14:33:38.882Z'
    slug: highlights-from-nada-new-york
    artists:
     - id: '54674262'
        itemType: artist
        updatedAt: '2021-08-31T14:14:06.952Z'
        createdAt: '2021-08-30T16:36:01.502Z'

        [...]

Then I can access the data perfectly fine.

My question: why is the DatoCMS .toMap() function formatting the two sets of data differently? They are mapping the exact same data, as they are both pulling from the same linked reference.

2

Ha! I had accidentally set it up and single linked field rather than multiple, so it wasn’t formatting it for a multiple item map! Doh!

Typing that all up helped me realize so I’ll leave it here for posterity lol.

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