Handling optional fields with mapOf()

[ericgoetz]

Hello, I have input JSON data in this shape:

{
  "-LCr5pXw_fN32IqNDr4E": {
    "bookCategory": "poetry",
    "locale": "en-us",
    "mediaType": "book",
    "publisher": "Pomelo Books",
    "title": "Sound Waves",
    "type": "poetry"
  },
  "-LDDHjkdY0306fZdvhEQ": {
    "ISBN13": "978-1534402966",
    "bookCategory": "fiction",
    "title": "What Can You Do with a Toolbox?",
    "type": "picturebook"
  }
}

That I want to be output as CSV approximately like this:

projectID, bookCategory, locale, mediaType, publisher, title, type, ISBN13
-LCr5pXw_fN32IqNDr4E,POETRY,en-us,book,Pomelo Books, Sound Waves,poetry,
"-LDDHjkdY0306fZdvhEQ,fiction,,,What Can You Do with a Toolbox?,picturebook,978-1534402966

The problem is that many of the fields are optional, which breaks mapOf. Is there a way to give mapOf a default value for missing fields? Here is my query, so far:

dasel -r json 'all().mapOf(projectID,.key(),title,.title,bookCategory,.bookCategory,type,.type,locale,.locale?).merge()' -w csv < test.json

[TomWright]

This feature has been added here: #355.

Docs are available here: https://daseldocs.tomwright.me/functions/ordefault

---

I'm working on a feature to support this.

Current version looks like this:

$ echo '{
  "-LCr5pXw_fN32IqNDr4E": {
    "bookCategory": "poetry",
    "locale": "en-us",
    "mediaType": "book",
    "publisher": "Pomelo Books",
    "title": "Sound Waves",
    "type": "poetry"
  },
  "-LDDHjkdY0306fZdvhEQ": {
    "ISBN13": "978-1534402966",
    "bookCategory": "fiction",
    "title": "What Can You Do with a Toolbox?",
    "type": "picturebook"
  }
}' | go run cmd/dasel/main.go -r json 'all().mapOf(projectId,key(),title,title,bookCategory,bookCategory,type,type,locale,orDefault(locale,string(unknown)))'
{
  "bookCategory": "poetry",
  "locale": "en-us",
  "projectId": "-LCr5pXw_fN32IqNDr4E",
  "title": "Sound Waves",
  "type": "poetry"
}
{
  "bookCategory": "fiction",
  "locale": "unknown",
  "projectId": "-LDDHjkdY0306fZdvhEQ",
  "title": "What Can You Do with a Toolbox?",
  "type": "picturebook"
}

I'm just thinking about alternatives or how it could be improved.
Any suggestions are welcome.

PR is here: #355