Selfhosted

Yep this for me too. Thankfully VSCode allows comments in its settings.json / launch.json files but most programs use strict JSON which doesn't allow comments

Yea, this is a deal breaker imo. My code tends to be 10 to 1 comments to lines of code ratio. Configuration even more so.

jsonc/json5 exists for this use case, but few tools actually use it, yaml is far more popular

Try the yaml language server by red hat, it comes with a docker compose validator.

But in general, off the top of my head, dashes = list. No dashes is a dictionary.

So this is a list:

thing:
    - 1
    - 2

And this is a dictionary:

dict:
    key1: value1
    key2: value2

And then when they can be combined into a list of dictionaries.

listofdicts:
    - key1dict1: value1dict1
    - key1dict2: value1dict2
      key2dict2: value2dict2

And then abother thing to note is that yaml wilL convert things into a string. So if you have ports 8080:80, this will be converted into a string, which is a clue that this is a string in a list, rather than a dictionary.

And like yeah, both the wonderful (and foss!) .json5 and Microsoft's semi-proprietary(?) .jsonc exist, but most projects just use their language's default JSON parser that doesn't recognize them. What I would personally love to see is .json5 support baked into the default JSON parsing libraries of Python, Go, etc. (Enabled by a flag, likely.) It's a superset of regular JSON and fully ES2019 compatible, so there shouldn't be any issues.