Create a JSON-to-Yaml converter that supports comments

This Issue is to track a sub-task related to gitlab-org/incubation-engineering/jamstack/meta#7 (moved).

In order to programatically create a yaml-file from interactive input fields I need a yaml.dump() method that supports the injection of comments into the resulting yaml.

It takes a valid JSON object and looks for special keys/strings and converts those to comments:

{
    "foods": {
        "#": "What to feed wild animals if they look like they are unable to feed themselves",
        "cats": "milk",
        "birds": ["seeds", "worms"],
        "#|hedgehogs": "Although hedgehogs like cat food, they should never be fed with milk",
        "hedgehogs": "cat food"
    },
    "predators": [
        "Cats",
        "Dogs",
        "# Tigers are rather rare in europe.",
        "Tigers"
    ]
}

Will become:

foods:
  # What to feed wild animals if they look like they are unable to feed
  # themselves
  cats: milk
  birds:
    - seeds
    - worms
  # Although hedgehogs like cat food, they should never be fed with milk
  hedgehogs: cat food
predators:
  - Cats
  - Dogs
  # Tigers are rather rare in europe.
  - Tigers

Rules:

Objects

• Generic comments in objects have the key "#". They will be injected before the first child of the object. There can be only one generic comment per object.
• Specific comments in objects have a key following the pattern "#|<id>" with <id> corresponding to a key of another child of the object. These will be injected before that child.

Arrays

• Entries in the array that are strings and start with # (including the space!) are determined to be comments and are injected as comments at the position they are inside the array.

Demo

https://youtu.be/iouVys2_kps?t=82