about jq [ ] syntax

what i learned

If you want to dump a list of objects you’re constructing from some other json you need to wrap your entire jq string in square brackets ( [] ). Otherwise you’ll be writing each object one at a time and that’s not valid JSON. For example, running something like

jq '.[] | {id: .id, title: .title, created: .created }'

returns →

{
    id: "123",
    title: "page 1",
    created: "2022-01-25T23:15:00.000Z"
}
{
    id: "124",
    title: "page 2",
    created: "2022-01-26T13:18:15.000Z"
}
{
    id: "125",
    title: "page 3",
    created: "2022-01-27T18:37:05.000Z"
}

This file is not valid JSON. However, if you wrap your entire expression in square brackets [] jq will group these all as a list of objects instead of appending each object at a time.

jq '[.[] | { id: .id, title: .title, created: .created }]'

returns →

[
  {
    "id": "123",
    "title": "page 1",
    "created": "2022-01-25T23:15:00.000Z"
  },
  {
    "id": "124",
    "title": "page 2",
    "created": "2022-01-26T13:18:15.000Z"
  },
  {
    "id": "125",
    "title": "page 3",
    "created": "2022-01-27T18:37:05.000Z"
  }
]

how i learned

Testing the til-notion-integration and markdownify-notion I tried reading a list of TILs I had saved in a JSON file. However, each object was separated by a new line - not a comma.

reference

The solution (after many failed google searches) was found on a GitHub issue answered by the creator of jq → github.com/stedolan/jq/issues/124