Netlify-cms: Can't parse date in front matter

[cetra3]

Describe the bug

NetlifyCMS breaks trying to parse dates of the format YYYY-MM-DD in the front-matter.

To Reproduce

Have a collections config like this:

collections:
  - name: "blog" # Used in routes, e.g., /admin/collections/blog
    label: "Blog" # Used in the UI
    folder: "content/blog" # The path to the folder where the documents are stored
    format: toml-frontmatter
    create: true # Allow users to create new documents in this collection
    fields: # The fields for each document, usually in front matter
      - {label: "Title", name: "title", widget: "string"}
      - {label: "Date", name: "date", widget: "date", format: "YYYY-MM-DD"}
      - {label: "Body", name: "body", widget: "markdown"}

Have a blog article with the following front matter:

title = "An Example Blog"
date = 2018-12-14
+++

This is an example blog

You will see this in the console:

Object { message: "Expected \"T\" but \"\\n\" found.", line: 3, column: 18, stack: "" }

Expected behavior

The collection date is parsed correctly.

[barthc]

@cetra3 I think the issue here is the frontmatter. The right format should look like so:

title = "An Example Blog"
date = "2018-12-14"
+++

May I ask, was the frontmatter generated via the CMS?

[cetra3]

The frontmatter was not generated by netlify, it was an existing blog that wasn't read.

According to the TOML spec dates do not require quotes:

Local Date
If you include only the date portion of an RFC 3339 formatted date-time, it will represent that entire day without any relation to an offset or timezone.
ld1 = 1979-05-27

[barthc]

@cetra3 investigated this issue further and the error seems to be coming from toml-j0.4 parser we are using to parse toml files. The parser only recognizes datetime format https://jakwings.github.io/toml-j0.4/. The simple workaround at the moment is to inclose your values in quotes.

[erquhart]

Good point @barthc. @cetra3 if you're up for opening an issue in the toml parser repo, that would be the place for a fix to occur.

[erquhart]

Actually, this isn't a bug so much as an improvement request: Netlify CMS currently supports TOML 0.4, which doesn't support this. The linked spec is for TOML 0.5, which doesn't yet have a stable release.

[cetra3]

Ah, that makes sense. The error message makes it look like it's coming from moment.js though.

[Keats]

Isn't https://github.com/toml-lang/toml/blob/master/versions/en/toml-v0.5.0.md a stable release from 2018?
It has a pre-release tag on the GH release page but so does every versions.

[callahad]

Looks like Netlify CMS is using toml-j0.4 as its parser, which does not support TOML 0.5, and has not seen active development for two years. Thus, resolving this likely means replacing the parser with another library.

[erquhart]

Yep, it's about the library we're using, not the spec.